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Research by Topic: Genetics
On Monday, the much anticipated MSSNG study which analyzed the entire DNA sequence of over 5000 people with autism was published. The press release can be found here. In it, the researchers found even more genes of interest to autism. Also, those with more of a specific type of mutation, copy number variations, had worse autism symptoms. […]
With hundreds of genes, thousands of environmental factors, and now sex being variables in determining risk for autism, where should science start? Over the decades researchers have been able to start narrowing down the combinations based on specific behaviors of interest, genes, and mechanisms which may narrow down which gene, which environmental factor and which […]
Overall, the scientific research examining the efficacy of oxytocin treatment in autism spectrum disorder has been mixed. On a previous podcast, studies on the way the oxytocin receptor was turned on and off were explained, which may account for variability in treatment response. This week, two studies in Japan show that specific mutations in the oxytocin […]
ASF fellow Dr. Donna Werling from UCSF will be presenting a webinar on June 22nd at 3PM EST. She will review data on use of genetics in humans and animals to study the causes of sex differences, and highlight ASF funding in moving forward on this topic. It is a great way to learn more […]
The genetics of autism is complicated. So scientists are taking a new approach. Instead of looking at genes associated with the bigger autism diagnosis, researchers at the University of Miami are considering how genes influence specific autism features present very early on in life. In this week’s podcast, two investigators, Devon Gangi and Nicole McDonald, explore […]
The types of gene mutations that contribute to autism are more diverse than previously thought, report researchers at University of California, San Diego School of Medicine in the March 24 online issue of The American Journal of Human Genetics. The findings, they say, represent a significant advance in efforts to unravel the genetic basis of autism […]
This week saw two studies advancing a new type of animal model for autism: the monkey. Environmental factors had been studied using this model, but this week saw the very first genetic model of autism in a monkey that also demonstrates features of autism. At the same time, another study published data on a new test to […]
Most patients with PCDH19 mutations exhibit a distinctive electroclinical pattern of focal seizures with affective symptoms, suggesting an epileptogenic dysfunction involving the frontotemporal limbic system. Awareness of this distinctive phenotype will likely enhance recognition of this disorder.
If you missed the October 1st webinar on Early Germline (sperm and egg) mutations and the heritability of autism, dont worry, we have it recorded on www.asfpodcast.org. The webinar explored emerging concepts in basic reproductive biology and also the heritability of ASDs. We know that autism is highly heritable, in the sense that ASD risk is higher among siblings, but it’s not shown to be highly “genetic” in the classic sense that these traits or genes are passed from generation to generation.
All are invited to the first in an ongoing series of free online symposia on the environmental epigenetics of autism, Oct. 1st at 1 pm Eastern. Speakers will include cell biologist Amander Clark, of UCLA, and geneticist Ryan Yuen, of Torontos SickKids Hospital.
Dup15, an organization representing families with one of the most common genetic causes of autism, held their annual family and science meeting in Orlando this week. Hear more about the science on the ASF podcast. www.asfpodcast.org
This week on the ASF podcast, we talk to @drdgsmith from Autism Speaks about the new study which turns skin cells into brain cells. It iis fascinating and important, but is not sufficient to study the brains of people with autism. Hear more on www.asfpodcast.org
Two separate studies published last week independently add to the body of evidence showing that genes and environment, together, are important to study risk factors in autism. The first is a study looking at the risk of autism in mothers who had diabetes and the other is an analysis of epigenetic markers from dads of kids with autism. While they tackle two different angles, they have a common thread: factors or mechanisms of the combined effects of genes/environment in ASD.
Researchers have been making tremendous progress in their efforts to understand the causes of autism, as well as which interventions may be most effective to help children with the disorder thrive.This work is especially critical as the number of children in the U.S. with autism grows. Approximately 1 in 68 children in the U.S. currently has autism, an increase of nearly 30 percent in recent years — at least partly due to greater awareness and improved diagnostics.
A Novel Approach of Homozygous Haplotype Sharing Identifies Candidate Genes in Autism Spectrum DisorderPublished April 8, 2015 in Human Genetics
A large scale analysis identifies candidate genes which may contain low-frequency recessive variations contributing to ASD
Neuronal Connectivity as a Convergent Target of Gene-environment Interactions that Confer Risk for Autism Spectrum DisordersPublished March 8, 2015 in Neurotoxicology and Teratology
This review briefly summarizes the evidence implicating dysfunctional signaling via Ca2 +-dependent mechanisms, extracellular signal-regulated kinases (ERK)/phosphatidylinositol-3-kinases (PI3K) and neuroliginneurexinSHANK as convergent molecular mechanisms in ASD, and then discusses examples of environmental chemicals for which there is emerging evidence of their potential to interfere with normal neuronal connectivity via perturbation of these signaling pathways.
Transcriptome Analysis Reveals Dysregulation of Innate Immune Response Genes and Neuronal Activity-Dependent Genes in AutismPublished December 10, 2014 in Nature
Using resources from the Autism BrainNet, a new study in brains affected by autism revealed a common factor of activated immune cells. Led by Dr. Dan Arking at Johns Hopkins, the project analyzed dats collected from 72 individuals, both with and without autism The findings compared gene expression across these two groups and from different brain banks. It also utilized a large dataset that contains data on existing autism risk genes. This represents the largest dataset so far in studying gene expression in the brains of autism. Previous studies have been too small to make meaningful conclusions, because of the lack of tissue available. The team, which also included the University of Alabama at Birmingham, saw that in individuals with ASD, a type of immune cell called microglia was always active, with genes for inflammation always being turned on. Arking noted that he did not think that the inflammation itself as the root cause of autism, but that it is the marker of a downstream effect. This type of inflammation is not well understood but it highlights the lack of current understanding about how innate immunity controls neural circuits, Dr. Andrew West, associated professor of neurology at the University of Alabama at Birmingham said.
The results of sequencing studies are helping autism researchers narrow down what genes to look for and where. They can now put forth a statistically sound estimate of the overall genetic contribution of de novo mutations of different categories to autism. However, they still cannot pinpoint the causal mutations for many cases of autism because the genomic background noise remains high.
Analyzing the sequences of more than 20,000 people, researchers have unearthed the largest and most robust list of autism genes so far, they reported in the journal Nature.These 50 high-confidence autism genes may help researchers understand the biological underpinnings of autism. The researchers found these genes by scouring the exomes, the protein-coding regions of the genome, looking for rare genetic glitches unique to people with autism.
The configuration of methyl tags that modify DNA in sperm change as men get older, according to a study published PLOS Genetics. These alterations may help explain why children of older fathers are at increased risk for neuropsychiatric disorders such as autism. Researchers at the University of Utah collected sperm from 17 men, once in the 1990s and again in 2008. They found that the distribution of methyl tags, a particular kind of DNA modification, shows relatively consistent changes over time in the sperm. However, the study does not necessarily prove that these altered patterns survive past fertilization or influence the risk of disorders such as autism.
Expansion of the Clinical Phenotype Associated with Mutations in Activity-Dependent Neuroprotective ProteinPublished July 23, 2014 in Journal of Medical Genetics
A new study has identified a genetic change in a recently identified autism-associated gene, which may provide further insight into the causes of autism. The study, now published online in the Journal of Medical Genetics, presents findings that likely represent a definitive clinical marker for some patients’ developmental disabilities. Researchers identified a genetic change in a newly recognized autism-associated gene, Activity-Dependent Neuroprotective Protein (ADNP), in a girl with developmental delay. This change in the ADNP gene helps explain the cause of developmental delay in this patient. This same genetic change in ADNP was also found in a boy who was diagnosed with autism.
A variation in the CHD8 gene has a strong likelihood of leading to a type of autism accompanied by digestive problems, a larger head and wide-set eyes, a study in Cell reports. This discovery is part of an emerging approach to studying the underlying mechanisms of autism and what those mean for people with the condition. Many research teams are trying to group subtypes of autism based on genetic profiles. This is the first time researchers have shown a definitive cause of autism from a genetic mutation.
People with autism tend to carry mutations that duplicate or delete several genes at once, according to a large study published in the American Journal of Human Genetics. Previous studies have shown that people with autism have more large deletions or duplications of DNA, also known as copy number variations (CNVs), than controls do. The new study, the largest to look at CNVs in people with autism thus far, confirms this finding. It also found that in people with autism, the CNVs are more likely to affect genes linked to intellectual disability and fragile X syndrome.
A small study published 3 April in Molecular Autism found that 98 percent of mothers of children with autism have unusual responses to sensory stimuli, including light, sound and touch. Up to 90 percent of children with autism show sensory problems, fixating on or avoiding certain smells, sounds or textures. As a result, the newest edition of the Diagnostic and Statistical Manual of Mental Disorders lists abnormal sensitivity in one or more of the five senses as a core diagnostic feature of autism. Its unclear whether genetics contributes to these sensory patterns, but a larger study examining the relationship between unusual sensory response, autism traits and additional disorders in family members may clarify the link.
Certain DNA repeats that increased exponentially during human evolution are directly related to the severity of autism symptoms, according to a preliminary study published in PLoS Genetics. The repeats each span 65 amino acids and are collectively referred to as DUF1220, for domain of unknown function. There are six types of these repeats, each with a slightly different sequence and all of which diverged from a common ancestor.
New evidence suggests that autism begins in the brain before birth when brain cells fail to develop properly. In this study, the abnormalities in the brain cells were not uniform, showing autism’s wide range of symptoms and severity. This better understanding of prenatal development of the brain cells of people with autism underscores the importance of early identification and intervention.
Researchers have developed a method to isolate a single mutant cell from thousands of others, they reported in the March issue of Nature Methods. The new approach will allow researchers to precisely engineer and study human cells without altering the genome. Ultimately, the method could be used to alter an individuals cells before returning them to his or her body.
A Higher Mutational Burden in Females Supports a Female Protective Model in Neurodevelopmental DisordersPublished February 27, 2014 in American Journal of Human Genetics
Researchers have more clues as to why more boys than girls are diagnosed with Autism Spectrum Disorder. A new study in the American Journal of Human Genetics suggests that for boys, it takes less of a genetic hit to cause autism than it does for girls. The study continues to say that when it does appear in girls, it is due to a much more severe genetic hit, usually resulting in much more severe autism symptoms.
A commercially available line of neurons generated from induced stem cells would serve as a good control for autism research, according to a study published in Psychopharmacology. Characterizing these neurons in detail shows that they express most of the genes linked to autism and look like typical, albeit immature, cells. Induced pluripotent stem cells, or iPSCs, are skin or blood cells reverted to a state from which they can become any cell in the body. Researchers can use the technique to turn cells from people with a neuropsychiatric disorder into neurons. They can then compare the neurons with those from controls to gain understanding of the disorder.
Scientists at Yale have identified which types of brain cells and regions of the brain are affected by genetic mutations linked to autism spectrum disorders. Researchers state that this new discovery has the potential for new types of autism treatments. We may not need to treat the whole brain, they say; only particular areas of the brain may be affected by autism at certain times.
Coexpression networks implicate human midfetal deep cortical projection neurons in the pathogenesis of autismPublished November 21, 2013 in Cell
"As techniques for studying the human genome have advanced, an increasing number of genes are being associated with ASD; it is important to find the connections between these ASD-linked genes in order to understand how they may contribute to ASD. A new resource called the BrainSpan1 atlas provides researchers with three dimensional maps showing when […]
People with autism show differences from controls in the levels of microRNAs, small noncoding bits of RNA, in the social and sound-processing parts of the brain. MicroRNAs, or miRNAs, bind to messenger RNAs, which code for protein, and flag them for degradation. Each miRNA can interfere with the production of several proteins. Of the more than 5,000 miRNAs and other small noncoding RNAs that the researchers screened, they found 3 miRNAs that are dysregulated in these regions in people with autism compared with controls.
The largest genetic analysis yet conducted of people lacking a brain structure called the corpus callosum shows that the condition shares many risk factors with autism. The study was published PLoS Genetics. The corpus callosum is the thick bundle of nerve fibers that connects the two hemispheres of the brain. People lacking this structure, a condition called agenesis of the corpus callosum (AgCC), often have social impairments, and roughly one-third of adults meet diagnostic criteria for autism. Children with autism seem to have a smaller corpus callosum than controls do.
New research shows a genetic link between individuals with autism and family members with specific speech and language difficulties otherwise unexplained by cognitive or physical problems. Researchers discovered that genes in a small region of two chromosomes can lead to one family member developing autism and another family member only developing language impairment.
Mutations in the autism-linked protein NHE6 may block the development of neuronal junctions by interfering with a growth factor called BDNF, according to a study published in the journal Neuron. The results suggest that drugs that enhance BDNF signaling could treat some forms of autism, the researchers say.
About one-third of people with autism suffer from epilepsy. This overlap suggests that the two disorders may have a common origin a theory borne out by examples of shared genetics. Mutations in GABRB3, a brain receptor linked to autism, are prevalent in severe childhood epilepsy, according to a study published in Nature. The study also found that many of the spontaneous mutations found in children with epilepsy overlap with those linked to autism and fragile X syndrome.
Researchers have optimized the production from stem cells of large numbers of a subtype of neurons involved in cognitive function. These neurons express the chemical messenger glutamate and are implicated in cognitive disorders such as autism. This technique, published in Translational Psychiatry, could generate enough neurons for large-scale screening of drugs.
Research published in the American Journal of Human Genetics found that people with ASDs often have just one copy of certain genes, when typically-developing people have two. This “mis-wiring” could alter the activity of nerve cells in the brain. The study found that the most commonly missing genes were linked to autophagy – a kind of waste-disposal and renewal process for cells. This study was led by Dr. Joseph Buxbaum, who is on ASF’s Scientific Advisory Board.
In a study recently published in the journal Nature, researchers discovered that autism genes are three to four times longer than the average gene expressed in neurons. According to the study, most mutations found in long genes tend to be discounted due to the fact that long genes generally have a higher probability of having a mutation, but the study says researchers think mutations in long genes should be looked at more carefully from now on.
Girls with autism tend to have smaller heads and bodies than their typically developing peers, whereas boys with the disorder tend to have average-sized heads and slightly larger bodies, report two recent studies. This shows another way that autism affects males and females differently.
Researchers at UNC have discovered that problems with a key group of enzymes known as topoisomerases can have profound effects on the genetic machinery behind brain development and potentially lead to autism spectrum disorder. Researchers believe this finding represents a great step forward in the search for environmental factors behind autism.
Researchers have recently discovered that two seemingly unrelated conditions, autism and cancer, share an unexpected connection. Some people with autism have specific mutated cancer or tumor genes that scientists believe caused their autism. While this does not apply to all people with autism, just the ones with the mutated gene, it is a very illuminating discovery in the field.
A new study published in JAMA Psychiatry found that men who fathered children at age 50 or older were nearly twice as likely to have a grandchild with autism compared to men who had children at a younger age. The study focused on age-related aspects and sought to control any other variables, such as socioeconomic status.
Two collaborative papers reveal the key steps of how mutations to the MeCP2 gene cause Rett Syndrome by impairing the interaction between MeCP2 and the NCoR/SMRT co-repressor.
Majority of Individuals with SHANK3 Gene Problems Have Both Autism and Severe Intellectual DisabilityPublished June 11, 2013 in Molecular Autism
Prospective study of 22q13 deletion syndrome and SHANK3 deficiency shows that the majority of individuals with a SHANK3 deficiency show both signs of autism and severe intellectual disability.
ASF Scientific Advisory Board Member, Joe Buxbaum, directed the first prospective study on the effects of Shank3 deficiency on a subtype of autism called 22q13 Deletion Syndrome, also known as Phelan-McDermid Syndrome.
Researchers at UCLA observed hyperactive firing rates in the brains of FMR1 knockout mice; mice engineered to have symptoms similar to those in ASD and Fragile X syndrome.
A new study using families from the Autism Genetic Resource Exchange (AGRE) finds that individuals with autism are 20% more likely to have copy-number variations of specific genes.
Scientists from George Washington University identified hundreds of molecular targets of the RORA gene. Of these molecular targets, 426 are linked to autism by the AutismKB database.
Methylomic Analysis of Monozygotic Twins Discordant for Autism Spectrum Disorder and Related Behavioural TraitsPublished April 23, 2013 in Molecular Psychiatry
This study suggests environmentally driven changes to the epigenome may contribute to the development of ASD and ASD-related behaviors. The study, which involved identical twins who were discordant for ASD and related traits, is the first large-scale examination of the role of genome-wide DNA methylation in ASD.
London study finds a higher rate of gene variations in the chromosome 16 region in males with autism compared to females.
Penn State researchers link autism to increased genetic change in “hotspots”, regions of the genome that are highly susceptible to mutation.
Recently published in JAMA Psychiatry, this study put forth a new autism risk factor: advanced grandpaternal age. Compared to men who had children between 20 and 24, men who fathered a child at 50+ were 1-2 times more likely to have a grandchild with autism. The findings suggest some autism risk factors can accumulate over generations.
A mother with two sons with autism helps advance research on neuroligin-4 mutations.
This Wake Forest Study compared the gene expression of gastrointestinal tissue in individuals with autism and compared it to individuals with Crohn’s Disease, ulcerative colitis and a control group. The study showed those with autism had a unique gene expression in their gastrointestinal tissue compared to the other groups studied.
Autism researchers and advocates are concerned about changes to the recruitment strategy of the National Childrens Study, which aims to enroll 100,000 pregnant women, monitor environmental exposures, and examine gene-environment interactions in the women and their children. The changes, which include forgoing door-to-door recruitment, may limit the generalizability of the findings.
SFARI Gene is an integrated resource for the autism research community. It is a publicly available, curated, web-based, searchable database for autism research. This resource is built on information extracted from the studies on molecular genetics and biology of Autism Spectrum Disorders (ASD). The genetic information includes data from linkage and association studies, cytogenetic abnormalities, and specific mutations associated with ASD.
Oxytocin and Vasopressin in Children and Adolescents With Autism Spectrum Disorders: Sex Differences and Associations With SymptomsPublished February 14, 2013 in Autism Research and Treatment
Following positive results of treatment studies using oxytocin (OT) and evidence of genetic variations in the OT-arginine vasopressin (AVP) pathway in individuals with ASD, a new study from UC Berkeley further examines the involvement of OT and AVP in ASD. Results suggest levels of OT in individuals with ASD may not be as low as previously believed. Moreover, the researchers found significant gender differences, including higher levels of OT in girls and higher levels of AVP in boys.
A review of current research shows that ASD affects females less frequently than males and suggests this difference may be due to several sex-differential genetic and hormonal factors.
Stem Cell Research Focusing on Autisms Genetic Mysteries Earns $2.125 Million Grant at Robert Wood Johnson Medical SchoolPublished February 12, 2013 in Newswise
Astroglial FMRP-Dependent Translational Down-regulation of mGluR5 Underlies Glutamate Transporter GLT1 Dysregulation in the Fragile X MousePublished February 7, 2013 in Human Molecular Genetics
This paper discusses the role fragile X mental retardation protein (FMRP) plays in protein expression in astrocytes, and suggests that FMRP loss in astrocytes may contribute to the development of fragile X.
Mutations in FAN1, a gene in the 15q13.3 chromosomal region, raise the risk of neuropsychiatric disorders including autism and schizophrenia, according to a new study published in the Proceedings of the National Academy of Sciences. The 15q13.3 chromosomal region is a hotbed of tiny genetic deletions and duplications connected to disorders of brain development.
SFARI: Rare, inherited mutations contribute to a significant proportion of autism cases according to two new studies published in Neuron.
Identification of Rare Recurrent Copy Number Variants in High-Risk Autism Families and Their Prevalence in a Large ASD PopulationPublished January 14, 2013 in PLOS One
Researchers discover 25 new autism-linked copy number variants.
Autism Genetic Testing: A Qualitative Study of Awareness, Attitudes, and Experiences among Parents of Children with Autism Spectrum Disorders.Published January 3, 2013 in Genetics in Medicine
This study provides insight into awareness, perspectives and experiences of ASD genetic testing among parents of autistic children.
UCSD researchers suggest genes linked to autism have higher mutation rates than other genes.
The Autism Sequencing Consortium: Large-Scale, High-Throughput Sequencing in Autism Spectrum DisordersPublished December 20, 2012 in Neuron
Dr. Joseph Buxbaum and team discuss the current state of ASD gene discovery and the benefits of a genomic technology called high-throughput sequencing.
ASF SAB member Dr. Joe Buxbaum on his new gene discoveries using high-throughput sequencing: “By identifying the many genetic roots of this disorder, we can better understand its biology, which in turn will allow us to develop more tailored treatments for individuals. It is a transformative time for genetic research in autism.”
Researchers link Fragile X syndrome protein to 93 genes that have been implicated in ASD. Lead investigator says the findings may lead to more detailed genetic tests.
A special issue of Disease Markers offers a comprehensive review on how current genetic research can be applied to biomarker development in ASD.
Four new studies of neuroligin-1 (NLGN1), a gene linked to autism, unravel its complex role in regulating synapses, the connections between neurons.
De novo mutations in six genes may contribute to 1% of simplex ASD cases.
Sponsored in part by ASF, the new Nature Outlook supplement on autism features articles on genetics, adulthood, brain imaging, diagnosis and more.
Researchers identified inactivating mutations in the gene BCKDK (Branched Chain Ketoacid Dehydrogenase Kinase) in consanguineous families with autism, epilepsy, and intellectual disability.
Unpublished data presented at the 2012 Society for Neuroscience annual meeting show at least 30 genes show altered expression in brain tissue of people with autism. The ongoing study aims to include more samples than previous postmortem studies, and includes samples lost in Harvards freezer malfunction.
Study finds that together, a large number of inherited, common genetic variations of very small effect can increase risk for autism. Suggests risk of inherited ASD is approximately 40% in simplex families and 60% in multiplex families.
Using Large Clinical Data Sets to Infer Pathogenicity for Rare Copy Number Variants in Autism CohortsPublished October 9, 2012 in Molecular Psychiatry
Copy number variants (CNVs) have a major role in the etiology of autism spectrum disorders (ASD), and several of these have reached statistical significance in casecontrol analyses. Nevertheless, current ASD cohorts are not large enough to detect very rare CNVs that may be causative or contributory (that is, risk alleles).
Levels of select PCB and PBDE congeners in human postmortem brain reveal possible environmental involvement in 15q11-q13 duplication autism spectrum disorder.Published October 1, 2012 in PubMed
Results demonstrate a novel paradigm by which specific POPs may predispose to genetic copy number variation of 15q11-q13.
Genetic tests are beginning to shed light on the causes of some autism spectrum disorders.
Experimental Drug may Treat Social Withdrawal Symptoms in Individuals with Fragile X Syndrome, the Most Common Known Genetic Cause of Autism.Published September 19, 2012 in Science Translational Medicine
Arbaclofen, also known as STX209, shows promise in its treatment of social symptoms associated with fragile x syndrome.
A new study finds that faulty neuronal circuits in autistic brains can be corrected even after the critical window of brain development.
“The current investigation interrogated single-nucleotide polymorphisms (SNPs) of individuals with ASD from the Autism Genetic Resource Exchange (AGRE) database. SNPs were mapped to Kyoto Encyclopedia of Genes and Genomes (KEGG)-derived pathways to identify affected cellular processes and develop a diagnostic test. “
The MET gene is shown to be a “potent modulator of key social brain circuitry in children and adolescents.” Researchers found that effects of high MET gene expression is more pronounced in individuals with ASD.
Findings highlight how genetic stratification may reduce heterogeneity and help elucidate the biological basis of complex neuropsychiatric disorders such as ASD.
“The human genome encodes the blueprint of life, but the function of the vast majority of its nearly three billion bases is unknown. The Encyclopedia of DNA Elements (ENCODE) project has systematically mapped regions of transcription, transcription factor association, chromatin structure and histone modification. These data enabled us to assign biochemical functions for 80% of the genome, in particular outside of the well-studied protein-coding regions. Many discovered candidate regulatory elements are physically associated with one another and with expressed genes, providing new insights into the mechanisms of gene regulation. The newly identified elements also show a statistical correspondence to sequence variants linked to human disease, and can thereby guide interpretation of this variation. Overall, the project provides new insights into the organization and regulation of our genes and genome, and is an expansive resource of functional annotations for biomedical research.”
With the latest annotation of the human genome, researchers have made new discoveries about common diseases
Dr. Eric Courchesne recently published his work he previewed at this year’s IMFAR in the “Journal of the American Academy of Child & Adolescent Psychiatry.”The mRNA expression abnormalities reliably observed in peripheral blood mononuclear cells, which are safely and easily assayed in infants, offer the first potential peripheral bloodbased, early biomarker panel of risk for autism in infants and toddlers. Future work should verify these biomarkers and evaluate whether they may also serve as indirect indices of deviant molecular neural mechanisms in autism.
Researchers found molecular basis for a cerebellar contribution to cognitive disorders such as autism.
Levels of Select PCB and PBDE Congeners in Human Postmortem Brain Reveal Possible Environmental Involvement in 15q11-q13 Duplication Autism Spectrum Disorder.Published August 29, 2012 in Environmental and Molecular Genetics
These results demonstrate a novel paradigm by which specific POPs may predispose to genetic copy number variation of 15q11-q13.
The diversity in mutation rate of SNP’s is dominated by the age of the father at conception of the child. The effect is an increase of about two mutations per year.
Scientists affiliated with the UC Davis MIND Institute have discovered how a defective gene causes brain changes that lead to the atypical social behavior characteristic of autism. The research offers a potential target for drugs to treat the condition.
Scientists track adult regression in Phelan-McDermid Syndrome, which is one of the autism-related syndromes with an identified genetic basis.
The influence of genetic mutations on the burden of any genetic disease can usefully be determined using family-based whole-genome or whole-exome sequencing approaches.
Emory University researchers identify mutations in an autism susceptibility gene that may explain why autism spectrum disorders affect four times as many boys as girls.
Researchers discuss the association between schizophrenia, bipolar disorder and ASD, and suggest the conditions share etiologic factors. Family history of schizophrenia or bipolar disorder was associated with increased ASD risk across three data sets. Individuals with schizophrenic siblings were 12 times more likely to have autism compared to those with no family history of schizophrenia.
In animal studies, we encourage more research on gene environment interactions, as well as experimental exposure to mixtures of compounds. Similarly, epidemiologic studies in humans with exceptionally high exposures can identify which pesticide classes are of greatest concern, and studies focused on gene environment are needed to determine if there are susceptible subpopulations at greater risk from pesticide exposures.
Researchers at the M.I.N.D Institute found decreased levels of adhesion molecules involved in immune cell migration in children with ASD. Reduced levels were associated with increased repetitive behaviors, abnormal brain growth, and impaired cognition.
Researchers led by Dr. Ben Philpot, an ASF funded mentor, at UNC School of Medicine found that seizures in individuals with Angelman syndrome could be linked to an imbalance in brain cell activity. Angelman syndrome exhibits frequent comorbidity with autism spectrum disorders.
Biological pathways revealed by the deeper list of ASD genes should narrow the targets for therapeutic intervention.
Vanderbilt University researchers examine oxytocin and serotonin systems as biomarkers for autism spectrum disorders.
A Common X-linked Inborn Error of Carnitine Biosynthesis May be a Risk Factor for Nondysmorphic Autism.Published May 22, 2012 in Proceedings of the National Academy of Sciences of the United States of America
These data suggest that dysregulation of carnitine metabolism may be important in nondysmorphic autism; that abnormalities of carnitine intake, loss, transport, or synthesis may be important in a larger fraction of nondysmorphic autism cases; and that the carnitine pathway may provide a novel target for therapy or prevention of autism.
Copy Number Variations suggest that the distinction between milder neuropsychiatric conditions from those of severe developmental impairment may be a consequence of increased mutational burden affecting more genes
FMRP-associated genes are under greater purifying selection than the remainder of genes and suggest they are especially dosage-sensitive targets of cognitive disorders.
Negative Allosteric Modulation of the mGluR5 Receptor Reduces Repetitive Behaviors and Rescues Social Deficits in Mouse Models of AutismPublished April 25, 2012 in Science Translational Medicine
Using a mouse model with behaviors relevant to the three diagnostic behavioral symptoms of autism, researchers used a genetic approach to reduce repetitive behaviors and partially reverse the striking lack of sociability in these mice.
Researchers today also say they’re beginning to make progress, perhaps for the first time, in understanding the autistic brain.
Researchers demonstrate that de-novo point mutations are overwhelmingly paternal in origin (4:1 bias) and positively correlated with paternal age, consistent with the modest increased risk for children of older fathers to develop ASD.
Results support polygenic models in which spontaneous coding mutations in any of a large number of genes increases risk by 5 to 20-fold. Despite the challenge posed by such models, results from de novo events and a large parallel case-control study provide strong evidence in favor of CHD8 and KATNAL2 as genuine autism risk factors.
Results indicate extreme locus heterogeneity but also provide a target for future discovery, diagnostics and therapeutics.
Control study provide strong evidence in favour of CHD8 and KATNAL2 as genuine autism risk factors.
Three teams of scientists working independently to understand the biology of autism have for the first time homed in on several gene mutations that they agree sharply increase the chances that a child will develop the disorder, and have found further evidence that the risk increases with the age of the parents, particularly the father.
For many families, the quest for the causes of autism has grown more urgent with the news that the estimated prevalence of the condition grew by 23% from 2006 to 2008, a Centers for Disease Control and Prevention report said last week.
On April 2, in honor of the fifth annual World Autism Awareness Day and HHS Autism Awareness Month the IACC has released its annual list of scientific advances that represent significant progress in the field.
A novel approach of homozygous haplotype sharing identifies candidate genes in autism spectrum disorder.Published April 1, 2012 in PubMed
Findings highlight the applicability of HH mapping in complex disorders such as ASD and offer an alternative approach to the analysis of genome-wide association data.
Newly Published Genetics/Brain Tissue Study Will Help Refine the Search for Specific Early Genetic Markers of Risk of Autism in Babies and ToddlersPublished March 22, 2012 in PLoS Genetics
A new study of autism published today in PLoS Genetics has discovered abnormal gene activity and gene deletions in the same brain region that also has a 67% overabundance of brain cells. This region the prefrontal cortexis involved in social, emotional, communication and language skills. The finding brings new understanding of what early genetic abnormalities lead to excess brain cells and to the abnormal brain wiring that cause core symptoms in autism. Importantly, the study also shows that gene activity abnormalities in autism change across the lifespan.
A proportion of risk for schizophrenia, bipolar disorder, and autism can be explained by rare mutations. Alleles can have specific effects on behavioral and neuroanatomical traits; however, expressivity is variable, particularly for neuropsychiatric phenotypes
CNV studies reflects the nature of rare alleles in general and will serve as a guide as we move forward into a new era of whole-genome sequencing.
Synaptic Dysfunction in Neurodevelopmental Disorders Associated with Autism and Intellectual Disabilities.Published March 1, 2012 in Cold Spring Harb Perspect Biol
The human studies unveiled the sensitivity of cognitive function to precise levels of different proteins.
A new study from the Infant Brain Imaging Network, which includes researchers at the Center for Autism Research at The Children’s Hospital of Philadelphia (CHOP), found significant differences in brain development starting at age 6 months in high-risk infants who later develop autism, compared to high-risk infants who did not develop autism.
A new study published in PLoS Genetics uses a combination of genetic and neurobiological approaches to confirm that synaptic mutations increase the risk of autism spectrum disorders (ASDs) and underlines the effect for modifier genes in these disorders.
For the first time, scientists have tracked the activity, across the lifespan, of an environmentally responsive regulatory mechanism that turns genes on and off in the brain’s executive hub.
New Research Might Help Explain How a Gene Mutation Found in some Autistic Individuals Leads to Difficulties in Processing Auditory Cues and Paying Spatial Attention to Sound.Published February 2, 2012 in Science Daily
New research from Cold Spring Harbor Laboratory (CSHL) might help explain how a gene mutation found in some autistic individuals leads to difficulties in processing auditory cues and paying spatial attention to sound.
Genetic and Functional Analyses of SHANK2 Mutations Suggest A Multiple Hit Model of Autism Spectrum DisordersPublished February 1, 2012 in PLOS Genetics
“Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disorders with a complex inheritance pattern. While many rare variants in synaptic proteins have been identified in patients with ASD, little is known about their effects at the synapse and their interactions with other genetic variations. Here, following the discovery of two de novo SHANK2 deletions by the Autism Genome Project, we identified a novel 421 kb de novo SHANK2 deletion in a patient with autism. We then sequenced SHANK2 in 455 patients with ASD and 431 controls and integrated these results with those reported by Berkel et al. 2010 (n?=?396 patients and n?=?659 controls). We observed a significant enrichment of variants affecting conserved amino acids in 29 of 851 (3.4%) patients and in 16 of 1,090 (1.5%) controls (P?=?0.004, OR?=?2.37, 95% CI?=?1.23-4.70). In neuronal cell cultures, the variants identified in patients were associated with a reduced synaptic density at dendrites compared to the variants only detected in controls (P?=?0.0013). Interestingly, the three patients with de novo SHANK2 deletions also carried inherited CNVs at 15q11-q13 previously associated with neuropsychiatric disorders. In two cases, the nicotinic receptor CHRNA7 was duplicated and in one case the synaptic translation repressor CYFIP1 was deleted. These results strengthen the role of synaptic gene dysfunction in ASD but also highlight the presence of putative modifier genes, which is in keeping with the “multiple hit model” for ASD. A better knowledge of these genetic interactions will be necessary to understand the complex inheritance pattern of ASD.”
A team led by researchers at the University of California, San Diego School of Medicine reports that newly discovered mutations in an evolved assembly of genes cause Joubert syndrome, a form of syndromic autism.
Although the genetic basis of autism is now well established, a growing body of research also suggests that environmental factors may play a role. Using a unique study design, a new study suggests that low birth weight is an important environmental factor contributing to the risk of autism spectrum disorder (ASD).
The anxiety and behavioral issues associated with excess MeCP2 protein result from overexpression of two genes (Crh [corticotropin-releasing hormone] and Oprm 1 [mu-opioid receptor MOR 1]), which may point the way to treating these problems in patients with too much of the protein, said Baylor College of Medicine scientists in a report that appears online in the journal Nature Genetics.
Director of the NIMH Dr. Tom Insel shares the NIMH’s Top 10 Research Advances for 2011.
While it is still unclear what’s different in the brains of people with autism spectrum disorders, more and more evidence from genetic and cell studies points to abnormalities in how neurons connect to each other.
In most cases, autism is caused by a combination of genetic factors, but some cases, such as Fragile X syndrome, can be traced to a variation in a single gene that causes overproduction of proteins in brain synapses. Now a new study led by the same MIT neuroscientist who made that discovery, finds that tuberous sclerosis is caused by a malfunction at the opposite end of the spectrum: underproduction of the synaptic proteins.
New research reveals that two genetic forms of autism, fragile X syndrome and tuberous sclerosis, are actually caused by opposite malfunctions – while fragile X is caused by overproduction of proteins at the synapse, tuberous sclerosis is caused by underproduction. Interestingly, while the causes of fragile X and tuberous sclerosis are distinctly different, both disorders […]
Research just released shows that scientists are finding new tools to help understand neurodevelopmental disorders like autism and fragile X syndrome.
Researchers debut the SHANK2 mouse and SHANK3 rat at the 2011 Society for Neuroscience annual meeting. SHANK2 belongs to the same family as SHANK3, a well-established autism candidate gene.
TBL1X Gene Involved In Autism Spectrum Disorder: Dr. Eden Martin from the Hussman Institute explains, “The SNP in TBL1X is associated with an increase in risk for ASD of about 15%.
Loss of FMR1 function is the most common genetic cause of autism. Understanding how this gene works is vital to finding new treatments to help Fragile X patients and others…
Recent research suggests that environmental factors may play a much greater role in autism risk than previously suspected and could even be more influential than genetic factors. These findings stem from a study of autism in twins, the largest of its kind, designed to model the genetic and environmental factors that contribute to the development […]
Having A Child With Autism Linked To Genetic Variant And Autoantibodies: Finding May Lead To Screening TestPublished October 20, 2011 in Medical News Today
A study by researchers at UC Davis has found that pregnant women with a particular gene variation are more likely to produce autoantibodies to the brains of their developing fetuses and that the children of these mothers are at greater risk of later being diagnosed with autism.
Research team from Beth Israel Deaconess Medical Center (BIDMC) has created a genetically engineered mouse with increased dosages of the Ube3 gene. And, like the patients who also harbor increased dosages of this single gene, the genetically engineered mice exhibit robust examples of all three traits considered hallmarks of autism: reduced social interaction, impaired communication and excessive repetitive behaviors. Findings provide further clues in understanding the brain defects that lead to the development of autism, and offer an important tool for future use by scientists and clinicians to test possible drug therapies.
Evidence found for the genetic basis of autism: Models of autism show that gene copy number controlsPublished October 5, 2011 in Science Daily
Scientists at Cold Spring Harbor Laboratory (CSHL) have discovered that one of the most common genetic alterations in autism — deletion of a 27-gene cluster on chromosome 16 — causes autism-like features. By generating mouse models of autism using a technique known as chromosome engineering, CSHL Professor Alea Mills and colleagues provide the first functional evidence that inheriting fewer copies of these genes leads to features resembling those used to diagnose children with autism.
A new strain of mice engineered to lack a gene with links to autism displays many of the hallmarks of the condition. It also responds to a drug in the same way as people with autism, which might open the way to new therapies for such people.
Absence of CNTNAP2 Leads to Epilepsy, Neuronal Migration Abnormalities, and Core Autism-Related DeficitsPublished September 30, 2011 in Cell
A new mouse model of autism, created by eliminating a gene strongly associated with the disorder in humans, shows promise for understanding the biology that underlies ASD and testing new treatments. By eliminating the CNTNAP2 gene (contactin associated protein-like 2), researchers were able to create mice with behaviors that closely mimicked those of its human […]
Animal Model Research Could Lead To The Development Of Diagnostic Tests For Autism Based On BiomarkersPublished September 14, 2011 in Medical News Today
The first transgenic mouse model of a rare and severe type of autism called Timothy Syndrome is improving the scientific understanding of autism spectrum disorder in general and may help researchers design more targeted interventions and treatments.
Researchers at the Center for Infection and Immunity (CII) at Columbia University’s Mailman School of Public Health and at the Harvard Medical School report that children with autism and gastrointestinal disturbances have altered expression of genes involved in digestion. These variations may contribute to changes in the types of bacteria in their intestines.
Researchers have for the first time identified two biologically different strains of autism in a major breakthrough being compared with the discovery of different forms of cancer in the 1960s. The findings, to be announced at an international autism conference in Perth today, are seen as a key step towards understanding the causes of autism and developing effective treatments as well as a cure. The findings bring hope that the communication, socialization and other difficulties that autistic children experience can be tackled more easily and earlier.
People with autism and attention deficit hyperactivity disorder (ADHD) share some of the same underlying genetic risk factors, according to a study published this month in Science Translational Medicine. This is one of the first studies to find risk variants that are common to both disorders.In searching for rare copy number variations (CNVs) deletions and duplications in genetic material in people with ADHD, the researchers found more than a dozen regions that include genes implicated in bipolar disorder, schizophrenia, intellectual disability and autism.
A study published August 15, 2011 in the journal Pediatrics found that infants with an older autistic sibling have a near 19 percent risk that they too will develop the disorder. The study is considered the largest autism study to follow infants for sibling recurrence.
A study of the genetic causes of autism confirmed that spontaneous or de novo mutations are present in a substantial number of families with only one child on the spectrum. These de novo mutations are not inherited from parents' DNA, arising instead in their egg or sperm or very early in embryonic development. Researchers compared […]
A recent study sheds light on how a variety of different mutations in genes that seemingly have little in common can each result in the symptoms of autism. To answer this question, researchers developed a molecular map of protein networks or "interactome" to identify how proteins associated with ASD interact with hundreds of other proteins. […]
Another study of spontaneous mutations identified four genes that are likely to play a causal role in the development of autism. Instead of searching more broadly for copy number variants throughout the genome, researchers focused exclusively on the protein-coding region of the genome called the exome. This approach has a greater potential to identify single […]
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A study found surprising consistency in molecular changes seen in the brains of people with autism across the spectrum, suggesting a common biological basis that may span multiple subtypes. Researchers analyzed postmortem brain tissue and found atypical patterns of gene expression common to many of the individuals with ASD. These findings may provide clues about […]
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In 2005, researchers from the University of North Carolina at Chapel Hill found that 2-year-old children with autism have brains up to 10 percent larger than children of the same age without autism. A follow-up study by UNC researchers has found that the children who had enlarged brains at age 2 continued to have enlarged brains at ages 4 and 5, but the amount of the enlargement was to the same degree found at age 2. This increased brain growth did not continue beyond 2 years of age and the changes detected at age 2 were due to overgrowth prior to that time point. In addition, the study found that the cortical enlargement was associated with increased folding on the surface of the brain (or increased surface area) and not an increase in the thickness of outer layer of the brain (or gray matter).
Multiple Recurrent De Novo CNVs, including Duplications of the 7q11.23 Williams Syndrome Region, are Strongly Associated with AutismPublished May 1, 2011 in Pediatrics
A recent collaborative study identified six genetic mutations that are strongly associated with autism spectrum disorder, including an area of DNA that likely holds clues to understanding the nature of human social behavior. The researchers estimate that these mutations represent only a few of the hundreds of spontaneously arising variants that are likely to increase […]
Researchers Reveal 18 Novel Subtype-Dependent Genetic Variants for Autism Spectrum Disorders and Identify Potential Genetic Markers for Diagnostic ScreeningPublished April 28, 2011 in Science Daily
By dividing individuals with autism spectrum disorders (ASD) into four subtypes according to similarity of symptoms and reanalyzing existing genome-wide genetic data on these individuals vs. controls, researchers at the George Washington University School of Medicine and Health Sciences have identified 18 novel and highly significant genetic markers for ASD. In addition, ten of the variants were associated with more than one ASD subtype, providing partial replication of these genetic markers. This study thus identifies candidate genes for ASD and potential subtype-dependent genetic markers for diagnostic screening.
It seems that the place where your brain transfers electricity between synapses and how your genes determine how these processes function, are tied to autism in one way or another. There can be genetically driven disturbances in this process that lead to varying levels of autism according to a new study of DNA from approximately 1,000 autistic children and their kin.
Scientists funded by Microsoft Corp. co-founder Paul Allen unveiled a $55 million computerized atlas of the human brain Tuesday, offering the first interactive research guide to the anatomy and genes that animate the mind.A project of the Seattle-based Allen Institute for Brain Science, the online atlas offers researchers a powerful new tool to understand where and how genes are at work in the brain. That could help them find new clues to conditions rooted in the brain, such as Alzheimer’s disease, autism and mental-health disorders like depression.
Led by the neurologist Dr. Patrick Cossette, the research team found a severe mutation of the synapsin gene (SYN1) in all members of a large French-Canadian family suffering from epilepsy, including individuals also suffering from autism.
With the help of two sets of brothers with autism, Johns Hopkins scientists have identified a gene associated with autism that appears to be linked very specifically to the severity of social interaction deficits. The gene, GRIP1 (glutamate receptor interacting protein 1), is a blueprint for a traffic-directing protein at synapses — those specialized contact points between brain cells across which chemical signals flow.
The Autism Tissue Program (ATP) is a postmortem brain tissue program created by the National Alliance for Autism Research (NAAR) for the purpose of supplying research scientists with neurological tissue samples of deceased Autistic individuals. Scientists, however, are not supplied with tissue samples from any other parts of the deceased individual, leading to frustration over […]
By mutating a single gene, researchers at MIT and Duke have produced mice with two of the most common traits of autism – compulsive, repetitive behavior and avoidance of social interaction. In this study, the researchers focused on one of the most common of those genes, known as shank3. Shank3 is found in synapses – the junctions between brain cells that allow them to communicate with each other. Feng, who joined MIT and the McGovern Institute last year, began studying shank3 a few years ago because he thought that synaptic proteins might contribute to autism and similar brain disorders, such as obsessive compulsive disorder.
New research on the genomics of autism confirms that the genetic roots of the disorder are highly complicated, but that common biological themes underlie this complexity. In the current study, researchers have implicated several new candidate genes and genomic variants as contributors to autism, and conclude that many more remain to be discovered. While the gene alterations are individually very rare, they mostly appear to disrupt genes that play important functional roles in brain development and nerve signaling.
This research on the genomics of autism confirms that the genetic roots of the disorder are highly complicated, but that common biological themes underlie this complexity. In the current study, researchers have implicated several new candidate genes and genomic variants as contributors to autism, and conclude that many more remain to be discovered. While the […]
George Washington University researchers have found that male and female sex hormones regulate expression of an important gene in neuronal cell culture through a mechanism that could explain not only higher levels of testosterone observed in some individuals with autism, but also why males have a higher incidence of autism than females. The gene, RORA, […]
Currently, the neurological basis of autism spectrum disorders (ASDs) is poorly understood. “Shank3 is a postsynaptic protein, whose disruption at the genetic level is thought to be responsible for the development of 22q13 deletion syndrome (Phelan-McDermid syndrome) and other non-syndromic ASDs”. In this study, mice with the Shank3 deletion were seen to exhibit “self-injurious repetitive […]
Georgianna Gould, Ph.D., research assistant professor of physiology in the Graduate School of Biomedical Sciences, is eyeing the role that serotonin plays in autism spectrum disorders. Serotonin is known for giving a sense of well-being and happiness. It is a neurotransmitter, a chemical that acts like a radio tower in the brain conveying signals among cells called neurons. Thirty percent of autism cases may have a serotonin component. In a recent paper in the Journal of Neurochemistry, Dr. Gould and colleagues showed that a medication called buspirone improved the social behaviors of mice. Buspirone is approved by the U.S. Food and Drug Administration for use in adults as an anti-anxiety and antidepressant adjuvant medication.
George Washington University researcher, Dr. Valerie Hu, Professor of Biochemistry and Molecular Biology, and her team at the School of Medicine and Health Sciences, have found that male and female sex hormones regulate expression of an important gene in neuronal cell culture through a mechanism that could explain not only higher levels of testosterone observed in some individuals with autism, but also why males have a higher incidence of autism than females.
Surprising View of Brain Formation: Discovery of a New Mechanism May Have Implications for a Host of DiseasesPublished February 10, 2011 in Science Daily
A study from The Scripps Research Institute has unveiled a surprising mechanism that controls brain formation. In the new study, Mueller and colleagues focused on a protein called reelin. They found reelin is a key player in the migration of new nerve cells to the neocortex, the part of the brain responsible for higher-order functions, such as language and movement. The findings have implications for understanding a host of diseases, including some forms of mental retardation, epilepsy, schizophrenia, and autism.
This study, performed by researchers at the University of Pennsylvania, analyzed the level of gene expression in children with autism, compared with a control group. The researchers hypothesized that the variability in the pattern of the overall of gene expression levels would be associated with variability in hippocampal-dependent behaviors, which include short-term memory and spatial […]
A second child is three times more likely to be diagnosed with autism if they are born within twelve months of their siblings, compared to those born three or more years apart, researchers from the Lazarsfeld Center for the Social Sciences at Columbia University, New York revealed in the journal Pediatrics. The investigators gathered information on 660,000 second children born in California between 1992 to 2002.
A Set Of Brain Proteins Is Found To Play A Role In Over 100 Brain Diseases And Provides A New Insight Into Evolution Of BehaviorPublished December 21, 2010 in Medical News Today
In research just published, scientists have studied human brain samples to isolate a set of proteins that accounts for over 130 brain diseases. The paper also shows an intriguing link between diseases and the evolution of the human brain.
Researchers from Mount Sinai School of Medicine have found that when one copy of the SHANK3 gene in mice is missing, nerve cells do not effectively communicate and do not show cellular properties associated with normal learning. This discovery may explain how mutations affecting SHANK3 may lead to autism spectrum disorders (ASDs). The research is currently published in Molecular Autism.
Altered Functional Connectivity in Frontal Lobe Circuits Is Associated with Variation in the Autism Risk Gene CNTNAP2Published December 1, 2010 in Pediatrics, Scott-Van Zeeland et al
People with a common variant of the CNTNAP2 gene, a gene associated with a heightened risk of autism, ADD/ADHD and other language difficulties, have a "disconnect" between their frontal lobe and other areas of the brain important for language, according to this fMRI study. The disconnect may help explain some of the language and communication […]
A post-mortem investigation measuring features of the different axons traveling beneath the cortical surface. The crux of the study is whether in autism there are changes in axons, "which are the conduit for neural communication." In comparison to control samples, autism brain tissue had fewer large axons connecting regions of the prefrontal cortex to the […]
Children with autism are far more likely to have deficits in their ability to produce cellular energy than are typically developing children, a new study by researchers at UC Davis has found. The study, published in the Journal of the American Medical Association (JAMA), found that cumulative damage and oxidative stress in mitochondria, the cell’s energy producer, could influence both the onset and severity of autism, suggesting a strong link between autism and mitochondrial defects.
An autism study by Yale School of Medicine researchers using functional magnetic resonance imaging (fMRI) has identified a pattern of brain activity that may characterize the genetic vulnerability to developing autism spectrum disorder (ASD). The team identified three distinct “neural signatures”: trait markers — brain regions with reduced activity in children with ASD and their unaffected siblings; state markers — brain areas with reduced activity found only in children with autism; and compensatory activity — enhanced activity seen only in unaffected siblings. The enhanced brain activity may reflect a developmental process by which these children overcome a genetic predisposition to develop ASD.
A collaborative effort between researchers at the Salk Institute for Biological Studies and the University of California, San Diego, successfully used human induced pluripotent stem (iPS) cells derived from patients with Rett syndrome to replicate autism in the lab and study the molecular pathogenesis of the disease.
A team from the University of California, San Diego, and the Salk Institute for Biological Studies devised a way to study brain cells from patients with autism, and found a way reverse cellular abnormalities in neurons that have been associated with autism, specifically Rett Syndrome.
In 1999, Baylor College of Medicine researcher Dr. Huda Zoghbi and her colleagues identified mutations in the gene called MECP2 as the culprit in a devastating neurological disorder called Rett syndrome . In new research in mice published in the current issue of the journal Nature, Zoghbi and her colleagues demonstrate that the loss of the protein MeCP2 in a special group of inhibitory nerve cells in the brain reproduces nearly all Rett syndrome features.
Scientists at the Wellcome Trust Centre for Human Genetics, University of Oxford, have identified a genetic variant which influences whether a person with dyslexia is more skilled with either the left or right hand. The finding identifies a novel gene for handedness and provides the first genetic evidence to support a much speculated link between handedness and a language-related disorder.
Researchers have uncovered a prominent genetic risk factor for autism spectrum disorders and schizophrenia is a small genomic deletion. Remarkably, they found the same deletion on chromosome 17 in 24 separate patients. This CNV was absent in 52,448 controls, making the finding statistically significant. Someone with this deletion is 13.58 times more likely to develop ASD or schizophrenia than is someone lacking this CNV. This gene mutation is also known to cause kidney disease (renal cysts and diabetes syndrome, RCAD).
Researchers at UCLA have discovered how an autism-risk gene rewires the brain, which could pave the way for treatments aimed at rebalancing brain circuits during early development. Dr. Geschwind and team examined the variations in brain function and connectivity resulting from two forms of the CNTNAP2 gene – one form of the gene increases the risk of autism. The researchers suspected that CNTNAP2 might have an important impact on brain activity. They used fMRI (functional magnetic resonance imaging) to scan 32 children’s brains while they were performing tasks related to learning. Only 16 of them had autism.The imaging results confirmed their suspicions. All the children with the autism-risk gene showed a disjointed brain, regardless of their diagnosis. Their frontal lobe was over-connected to itself, while connection to the rest of the brain was poor, especially with the back of the brain. There was also a difference between how the left and right sides of the brain connected with each other, depending on which CNTNAP2 version the child carried.The authors believe their findings could help identify autism risk earlier, and eventually lead to interventions that could enhance connections between the frontal lobe and the left side of the brain.
Studies have suggested associations between immune response and idiopathic disorders (such as autism). This study explores associations between parental autoimmune disorders and children's diagnosis of autism by linking. The study found associations between parental autoimmune disorders and autism spectrum disorders, suggesting parental autoimmune disorders may represent a pathway that warrants more detailed investigation.
The last two decades have seen tremendous progress in understanding the genetic basis of human brain disorders. Research developments in this area have revealed fundamental insights into the genes and molecular pathways that underlie neurological and psychiatric diseases. In a new series of review articles, experts in the field discuss exciting recent advances in neurogenetics research and the potential implications for the treatment of these devastating disorders.
Insight into the role that MHC plays in the nervous system and may enhance our understanding of the factors that can contribute to neuropsychiatric disorders like autism and schizophrenia. Increased levels of a protein called major histocompatibility complex, or MHC, in fetal neurons may be a factor development of autism or schizophrenia.
A pregnant woman’s immune response to viral infections may induce subtle neurological changes in the unborn child that can lead to an increased risk for neurodevelopmental disorders including schizophrenia and autism.
Full-term neonates with jaundice are at greatly increased risk of later being diagnosed with a disorder of psychological development, a Danish study found. Neonatal jaundice typically is caused by increased bilirubin production and inadequate liver excretory function. Recent research has suggested that even moderate bilirubin exposure in very young children can be harmful, possibly leading to impairments in their development. They found that jaundice was more common among boys, infants born preterm, infants with congenital malformations, and low-birthweight infants.
A new study, led by researchers at Washington University School of Medicine in St. Louis, found mild traits, not strong enough to provoke a diagnosis of autism, seem to be present in the siblings of affected children at significantly higher rates than seen in the general population. Siblings of children with autism have more frequent language delays and other subtle characteristics of the disorder than previously understood. Girls also may be mildly affected more often than recognized in the past.
Researchers at the Center for Neuroscience Research at Children’s National Medical Center have discovered that the two major types of signaling pathways activated during brain cell development. This knowledge may help scientists design new ways to induce the brain to repair itself when these signals are interrupted, and indicate a need for further research to determine whether disruptions of these pathways in early brain development could lead to common neurodevelopmental disorders such as epilepsy, cerebral palsy, autism, Down syndrome, ADHD, and intellectual disabilities.
If a boy’s X-chromosome is missing the PTCHD1 gene or other nearby DNA sequences, they will be at high risk of developing ASD or intellectual disability. Girls are different in that, even if they are missing one PTCHD1 gene, by nature they always carry a second X-chromosome, shielding them from ASD.
An international study led by University of Montreal scientists suggests family history may not be a good predictor of the presence of mutations predisposing to autism or schizophrenia. The findings show how new or de novo gene mutations – alterations of the cell’s DNA – play a role in these devastating conditions.
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A clue to the causes of autism and mental retardation lies in the synapse, the tiny intercellular junction that rapidly transfers information from one neuron to the next. According to neuroscientists at Tufts University School of Medicine, with students from the Sackler School of Graduate Biomedical Sciences at Tufts, a protein called APC (adenomatous polyposis coli) plays a key role in synapse maturation, and APC dysfunction prevents the synapse function required for typical learning and memory.
Mutations in a single gene can cause several types of developmental brain abnormalities that experts have traditionally considered different disorders. With support from the National Institutes of Health, researchers found those mutations through whole exome sequencing ? a new gene scanning technology that cuts the cost and time of searching for rare mutations. Whole exome sequencing can be applied to dozens of other rare genetic disorders where the culprit genes have so far evaded discovery. Such information can help couples assess the risk of passing on genetic disorders to their children. It can also offer insights into disease mechanisms and treatments.
DNA for each individual contains variants that are more or less common in the overall population.Some gene variations are actually genetic deletions, where sections of DNA ‘code’ are missing entirely. These variants are likely to have important effects on gene function and, therefore, likely to contribute to diseases associated with that gene. But what happens when multiple genes are disrupted in a single family?
Together with colleagues from an international research group, autism researcher Christopher Gillberg of the University of Gothenburg, Sweden, has found in a new study that autism can be partially explained by abnormalities in certain genes. The group’s results could, in the long run, pave the way for more appropriate treatments for autism.In the article the group reveals that a survey of 1,000 individuals with autism and 1,300 without showed that Copy Number Variants (CNVs) sub-microscopic abnormalities in the chromosomes are heavily over-represented in autistic people.
Researchers at Emory University School of Medicine have identified a potential new strategy for treating fragile X syndrome — the most common inherited cause of intellectual disability. The researchers have found that a class of drugs called phosphoinositide-3 (PI3) kinase inhibitors can correct defects in the anatomy of neurons seen in a mouse model of fragile X syndrome.
Cascades of genetic signals determine which neurotransmitter a brain cell will ultimately use to communicate with other cells. Now a pair of reports from biologists at the University of California, San Diego, have shown for the first time that electrical activity in these developing neurons can alter their chemical fate — and change an animal’s behavior — by tweaking this genetic program.
A genome-wide analysis reveals that people with ASDs carry a higher load of rare copy-number variants — segments of DNA for which the copy number differs between individual genomes — which are either inherited or arise de novo. The results implicate several novel genes as ASD candidates and point to the importance of cellular proliferation, […]
The first “test tube baby” was born in 1978. With advances in reproductive science, an estimated one percent of all American babies are now born each year through in vitro fertilization (IVF). But IVF and other assisted fertility treatments may be solving one problem by creating another, suggests new evidence from Tel Aviv University.
Mount Sinai researchers and the Autism Genome Project Consortium (AGP) announced that they have identified new autism susceptibility genes that may lead to the development of new treatment approaches. These genes, which include SHANK2, SYNGAP1, DLGAP2 and the X-linked DDX53-PTCHD1 locus, primarily belong to synapse-related pathways, while others are involved in cellular proliferation, projection and motility, and intracellular signaling
This study analysed the genome-wide characteristics of rare (
Using microarrays, the department of molecular human genetics in Heidelberg, Germany identified de novo copy number variations in the SHANK2 synaptic scaffolding gene in two unrelated individuals with autism-spectrum disorder (ASD) and mental retardation. DNA sequencing of SHANK2 in 396 individuals with ASD, 184 individuals with mental retardation and 659 unaffected individuals (controls) revealed additional […]
Recent genetic studies have revealed some common themes: considerable locus heterogeneity, variable expressivity for the same mutation, and a role for multiple disruptive events in the same individual affecting genes in common pathways.
IntegraGen SA, a French biotechnology company dedicated to gene discovery, announced today the publication of the results of a collaborative study reporting the use of a combined analysis of multiple genetic variants in a genetic score to help identify individuals at high risk of developing autism.
Schizophrenia involves some of the same genetic variations as autism and attention deficit disorders, a new whole-genome study has confirmed. In an effort to assess some of the common genetic variations that might underpin this fairly common but thorny mental illness, researchers sequenced DNA from 1,735 adults with schizophrenia and 3,485 healthy adults. Across the patients that had the disease, the researchers found many frequent variations related to copying or deleting genes, known as copy-number variations.
Researchers at UT Southwestern Medical Center have discovered how the genetic mutation that causes Fragile X syndrome, the most common form of inherited mental retardation, interferes with the “pruning” of nerve connections in the brain. They found Fragile X is caused by a mutation in a single gene, Fmr1, on the X chromosome. The gene codes for a protein called FMRP, which plays a role in learning and memory but whose full function is unknown. The protein’s role in pruning nerve connections had been unclear.
Researchers identified a rare genetic mutation that may open a new avenue for treating Tourette syndrome in a study published Wednesday that examined a family in which the father and all eight children suffer from the neurological disorder.The family’s mutation affected a gene required to produce histamine. Pharmaceutical companies are already developing drugs for other conditions that target the brain’s histamine system. The study’s researchers are planning a clinical trial of adults with Tourette to see if those drugs would help control the motor and vocal tics that characterize the condition.
A new study by researchers at The George Washington University School of Medicine and Health Sciences’ Department of Biochemistry and Molecular Biology raises hope that autism may be more easily diagnosed and that its effects may be more reversible than previously thought. Researchers have identified potentially removable chemical tags (called “methyl groups”) on specific genes of autistic individuals that led to gene silencing. They also observed these changes in cells derived from blood, opening the way to molecular screening for autism using a blood test.
New research from the lab of Michael Greenberg, Nathan Marsh Pusey professor and chair of neurobiology at HMS, in collaboration with bioinformatics specialist and neuroscientist Gabriel Kreiman, assistant professor of ophthalmology at Children’s Hospital, Boston, has found that a particular set of RNA molecules widely considered to be no more than a genomic oddity are actually major players in brain development – and are essential for regulating the process by which neurons absorb the outside world into their genetic machinery.
A new discovery raises hope that autism may be more easily diagnosed and that its effects may be more reversible than previously thought. In a new study appearing online in The FASEB Journal, scientists have identified a way to detect the disorder using blood and have discovered that drugs which affect the methylation state (“DNA tagging”) of genes could reverse autism’s effects. This type of drug is already being used in some cancer treatments.
Two genes have been associated with autistic spectrum disorders (ASD) in a new study of 661 families. Researchers writing in BioMed Central’s newly launched journal Molecular Autism found that variations in the genes for two brain proteins, LRRN3 and LRRTM3, were significantly associated with susceptibility to ASD.
A large study from Children’s Hospital Boston and the Boston-based Autism Consortium finds that a genetic test that samples the entire genome, known as chromosomal microarray analysis, has about three times the detection rate for genetic changes related to autism spectrum disorders (ASDs) than standard tests.
A genetic link between schizophrenia and autism is enabling researchers to study the effectiveness of drugs used to treat both illnesses. Dr. Steve Clapcote from the University of Leeds’s Faculty of Biological Sciences will be analyzing behavior displayed by mice with a genetic mutation linked to schizophrenia and autism and seeing how antipsychotic drugs affect their behavioral abnormalities.
When a gene implicated in human autism is disabled in mice, the rodents show learning problems and obsessive, repetitive behaviors, researchers at UT Southwestern Medical Center have found. The researchers also report that a drug affecting a specific type of nerve function reduced the obsessive behavior in the animals, suggesting a potential way to treat repetitive behaviors in humans
Alison Singer says link between autism, vaccinations debunked but research progressing. But, she says, new science is overshadowed as some cling to discredited study. Some parents put kids in danger by still avoiding vaccines, trying dicey “therapies”. New research should move forward with science as a guide.
Researchers have known for years that when one identical twin has autism, the other is also likely to be diagnosed with it – evidence that autism likely has a genetic component. Recent studies support that theory. Researchers at Kennedy Krieger Institute studied 277 pairs of twins and found that when one identical twin had the disorder, the other developed it 88 percent of the time; for fraternal twins, that figure was 31 percent.
TIME recognized New Research on Autism as #7 of its Top 10 Medical Breakthroughs of 2009.
Researchers at the University of North Carolina at Chapel Hill School of Medicine have found that the 22q11 gene deletion — a mutation that confers the highest known genetic risk for schizophrenia — is associated with changes in the development of the brain that ultimately affect how its circuit elements are assembled.The researchers would now like to figure out how these alterations in the circuitry of the brain affect the behavior of the mouse. They also hope that understanding the “mis-wiring” of the brain in a genetic animal model of schizophrenia would help them understand the causes of the disease in the general population
An international consortium of researchers, including three from the University of Utah, has discovered yet another genetic link to autism. Studying the genes of more than 1,000 families — including 150 from Utah — who have more than one person with the disorder, the researchers found a region on chromosome 5 that is strongly associated with autism.
In one of the first studies of its kind, an international team of researchers has uncovered a single-letter change in the genetic code that is associated with autism. The finding, published in the October 8 issue of the journal Nature, implicates a neuronal gene not previously tied to the disorder and more broadly, underscores a role for common DNA variation. In addition, the new research highlights two other regions of the genome, which are likely to contain rare genetic differences that may also influence autism risk.
Genome-Wide Analyses of Exonic Copy Number Variants in a Family-Based Study Point to Novel Autism Susceptibility GenesPublished June 1, 2009 in PLOS Genetics, Bucan M, Abrahams BS, Wang K, Glessner JT, Herman EI, et al.
The study identified 27 different genetic regions where rare copy number variations – missing or extra copies of DNA segments – were found in the genes of children with autism spectrum disorders, but not in the healthy controls. The researchers, including geneticists from the University of Pennsylvania School of Medicine and The Children's Hospital of […]
High-density SNP association study of the 17q21 chromosomal region linked to autism identifies CACNA1G as a novel candidate genePublished May 1, 2009 in Molecular Psychiatry, Strom, Stone, Bosch, Merriman, Cantor, Geschwind, and Nelson
(From a UCLA press release) UCLA scientists have discovered a variant of a gene called CACNA1G that may increase a child's risk of developing autism, particularly in boys. "We found that a common form of the gene occurs more frequently in the DNA of families that have two or more sons affected by autism, but […]
A newly identified genetic variant could account for up to 15 percent of autism cases, say researchers who studied genes that are important in connecting brain cells. Researchers say the variant is carried by about 65 per cent of people with autism.
A Common Genetic variant in the neurexin superfamily member CNTNAP2 increases Familial Risk of AutismPublished December 1, 2008 in American Journal of Human Genetics, Arking, Cutler, et al
Autism is a childhood neuropsychiatric disorder that, despite exhibiting high heritability, has largely eluded efforts to identify specific genetic variants underlying its etiology. We performed a two-stage genetic study in which genome-wide linkage and family-based association mapping was followed up by association and replication studies in an independent sample. We identified a common polymorphism in […]
Serum antibodies in 100 mothers of children with autistic disorder (MCAD) were compared to 100 age-matched mothers with unaffected children (MUC) using as antigenic substrates human and rodent fetal and adult brain tissues, GFAP, and MBP. MCAD had significantly more individuals with Western immunoblot bands at 36 kDa in human fetal and rodent embryonic brain […]
Linkage, Association, and Gene Expression Analyses Identify CNTNAP2 as an Autism-Susceptibility GenePublished January 1, 2008 in American Journal of Human Genetics, Alarcon, Abrahams, et al.
Autism is a genetically complex neurodevelopmental syndrome in which language deficits are a core feature. We describe results from two complimentary approaches used to identify risk variants on chromosome 7 that likely contribute to the etiology of autism. A two-stage association study tested 2758 SNPs across a 10 Mb 7q35 language-related autism QTL in AGRE […]
Molecular Cytogenetic Analysis and Resequencing of Contactin Associate Protein-Like 2 in Autism Spectrum DisordersPublished December 31, 1969
Autism spectrum disorders (ASD) are a group of related neurodevelopmental syndromes with complex genetic etiology. We identified a de novo chromosome 7q inversion disrupting Autism susceptibility candidate 2 (AUTS2) and Contactin Associated Protein-Like 2 (CNTNAP2) in a child with cognitive and social delay. We focused our initial analysis on CNTNAP2 based on our demonstration of […]
Autism is a profound disorder of neurodevelopment with poorly understood biological origins. A potential role for maternal autoantibodies in the etiology of some cases of autism has been proposed in previous studies To investigate this hypothesis, maternal plasma antibodies against human fetal and adult brain proteins were analyzed by western blot in 61 mothers of […]
Mutations in the gene encoding the transcriptional repressor methyl-CpG binding protein 2 (MeCP2) cause the neurodevelopmental disorder Rett syndrome. Loss of function as well as increased dosage of the MECP2 gene cause a host of neuropsychiatric disorders. To explore the molecular mechanism(s) underlying these disorders, we examined gene expression patterns in the hypothalamus of mice […]
Axon formation is fundamental for brain development and function. TSC1 and TSC2 are two genes, mutations in which cause tuberous sclerosis complex (TSC), a disease characterized by tumor predisposition and neurological abnormalities including epilepsy, mental retardation, and autism. Here we show that Tsc1 and Tsc2 have critical functions in mammalian axon formation and growth. Overexpression […]
Autism is a childhood neurodevelopmental disorder with a strong genetic component, yet the identification of autism susceptibility loci remains elusive. We investigated 180 autism probands and 372 control subjects by array comparative genomic hybridization (aCGH) using a 19K whole-genome tiling path bacterial artificial chromosome microarray to identify submicroscopic chromosomal rearrangements specific to autism. We discovered […]
One proposed cause of ASD is exposure of the fetal brain to maternal autoantibodies during pregnancy [Dalton, P., Deacon, R., Blamire, A., Pike, M., McKinlay, I., Stein, J., Styles, P., Vincent, A., 2003. Maternal neuronal antibodies associated with autism and a language disorder. Ann. Neurol. 53, 533-537]. To provide evidence for this hypothesis, four rhesus […]
To find inherited causes of autism-spectrum disorders, we studied families in which parents share ancestors, enhancing the role of inherited factors. We mapped several loci, some containing large, inherited, homozygous deletions that are likely mutations. The largest deletions implicated genes, including PCDH10 (protocadherin 10) and DIA1 (deleted in autism1, or c3orf58), whose level of expression […]
We have identified a novel, recurrent microdeletion and a reciprocal microduplication that carry substantial susceptibility to autism and appear to account for approximately 1% of cases. We did not identify other regions with similar aggregations of large de novo mutations. Among the AGRE families, we observed five instances of a de novo deletion of 593 […]
Schizophrenia is an etiologically heterogeneous psychiatric disease, which exists in familial and nonfamilial (sporadic) forms. Here, we examine the possibility that rare de novo copy number (CN) mutations with relatively high penetrance contribute to the genetic component of schizophrenia. We carried out a whole-genome scan and implemented a number of steps for finding and confirming […]