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Research by Topic: Gender
Previously understudied, a special issue of the science journal Molecular Autism dedicates space to females with ASD. Leading the list is a summary of the October, 2014 meeting on gender issues co-sponsored by ASF. Download all of the articles free by clicking here http://www.molecularautism.com/series/sexdifferences?utm_campaign=BMC18421C&utm_medium=BMCemail&utm_source=Teradata
A new study from the Kennedy Krieger Institute in Baltimore indicates that generally girls are getting diagnosed with autism at a later age than boys, perhaps because they exhibit different and less severe symptoms. The study is based on data from the Institute’s Interactive Autism Network, an online registry of almost 50,000 individuals and their families affected by autism. In the registry, age of first diagnosis was available for 9,932 children, and 5,103 had completed the Social Responsiveness Scale, which identifies the presence and severity of social impairment.
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 group in the UK conducted an exhaustive literature search surrounding current studies on sex and gender differences and autism spectrum disorders. This literature search grouped studies into four categories, focusing on behavioral features, diagnosis and disparity issues, causes of disparity, and developmental trajectory. These same topics will be discussed on October 29 at the Sex and Gender Differences in ASD science workshop in New York, sponsored by the Autism Science Foundation and Autism Speaks.
Dysregulation of Estrogen Receptor Beta, Aromatase, and ER Co-Activators in the Middle Frontal Gyrus of Autism Spectrum Disorder SubjectsPublished September 9, 2014 in Molecular Autism
In a study conducted at the medical college of Georgia, researchers found a reduction in estrogen receptors in the frontal cortex of brains of boys with ASD. They also found a decrease in the expression of an enzyme that regulates hormones in the brain. The researchers suggest that this may be one of the reasons for the sex difference in ASD, but these findings also point to a potential gene/environment interaction in the disorder. One of the drawback of this study, however, is that there were only 13 samples in each group. The reality is that there is a shortage of available brain tissue to study. If you’d like to learn more about brain tissue donation that will further autism research, visit TakesBrains.org.
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 Cambridge study that used brain imaging samples of individuals with autism, led by Dr. Simon Baron-Cohen, found evidence that autism affects sexes differently. The study showed that women who have the condition demonstrate neuroanatomical masculinization, which suggests that women with autism have more masculine brains. Dr. Baron-Cohen argues that this study reinforces that researchers “should not blindly assume that everything found in males with autism applies to females.”News Article: http://www.cambridge-news.co.uk/Education/Universities/Autism-affects-sexes-differently-20130809000647.htm
“Why do boys get diagnosed with autism four times as often as girls? New research, including some of the latest data from the International Society for Autism Research annual conference last week, addresses this question, one of the biggest mysteries in the field.”
London study finds a higher rate of gene variations in the chromosome 16 region in males with autism compared to females.
This study examined the hypothesis that a protective component of the female sex protects females from autistic behavioral impairment. The results indicate that greater familial risk may be associated with ASD in females, and males may require fewer familial risk factors to reach a similar impairment threshold. The authors hope the study will provide insight into the ASD sex ratio and aid future genetic research.
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.
How Different Are Girls and Boys Above and Below the Diagnostic Threshold for Autism Spectrum Disorders?Published August 1, 2012 in Journal of the American Academy of Child and Adolescent Psychiatry
A study finds that despite showing similar autistic traits, girls are less likely than boys to meet diagnostic criteria for ASD if no other intellectual or behavioral issues are present. The authors suggest the results might reflect biased diagnosis or better adaptation in girls.
According to a study published in the American Journal of Medical Genetics, Women who have a milder version of the fragile X mutation, which can lead to the full mutation in their children, have some features of autism.
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.
From Autism Science Foundation(March 29, 2012New York) The Centers for Disease Control in Atlanta today reported that 1 in 88 children (1 in 48 boys) is diagnosed with an autism spectrum disorder (ASD). Previous reports had pegged the number at 1 in 110.
The Centers for Disease Control in Atlanta today reported that 1 in 88 children (1 in 54 boys) is diagnosed with an autism spectrum disorder (ASD). Previous reports had pegged the number at 1 in 110.
A bone-marrow transplant can treat a mouse version of Rett syndrome, a severe autism spectrum disorder that affects roughly 1 in 10,00020,000 girls born worldwide (boys with the disease typically die within a few weeks of birth).
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.
In the largest study of brain development in preschoolers with autism to date, a study by UC Davis MIND Institute researchers has found that 3-year-old boys with regressive autism, but not early onset autism, have larger brains than their healthy counterparts.
A small study found that male children with autism had larger brain weights and 67% more prefrontal brain neurons than children without autism.
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%.
UCLA researchers have found the connections between brain regions that are important for language and social skills grow much more slowly in boys with autism than in non-autistic children…
Boys with autism tend to grow faster as babies, with differences from typically developing infants seen in their head size, height and weight, a new study says. Researchers said the findings may offer new clues about the underlying mechanisms of autism. A larger head size probably means the children also have a larger brain.
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 […]
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, […]
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.
Smoking during pregnancy may interfere with brain development. New animal research shows maternal smoking affects genes important in the formation and action of a fatty brain substance called myelin that insulates brain cell connections. The finding may explain why the children of mothers who smoked during pregnancy are more likely to develop attention deficit hyperactivity disorder, depression, autism, drug abuse, and other psychiatric disorders.
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).
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.
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.
This new study in the journal of Pediatrics indicated that there was no increased risk of Autism Spectrum Disorder associated with receipt of thimerosal-containing vaccines. The study also found no increased risk for any of the subtypes of Autism Spectrum Disorder, including ASD with regression. In addition, it found no increased risk of Autism Spectrum […]
Study sought to describe autism spectrum disorder (ASD) population characteristics and changes in identified prevalence across 3 time periods. Children with a potential ASD were identified through records abstraction at multiple sources with clinician review based on Diagnostic and Statistical Manual (DSM-IV-TR) criteria. Multisite, population-based data from the Autism and Developmental Disabilities Monitoring (ADDM) Network […]
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.
Longitude Magnetic Resonance Imaging Study of Cortical Development Through Early Childhood in AutismPublished March 1, 2010 in Journal of Neuroscience, Courchesne et al
The first longitudinal study of brain growth in toddlers at the time symptoms of autism are becoming clinically apparent using structural MRI scans at multiple time points beginning at 1.5 years up to 5 years of age. They collected 193 scans on 41 toddlers who received a confirmed diagnosis of autistic disorder at approximately 48 […]
Scientists at the University of Cambridge have discovered that the brains of individuals with autism are less active when engaged in self-reflective thought. The study published in the journal Brain provides new evidence for the neural correlates of self-awareness and a new window into understanding social difficulties in autism spectrum conditions.
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 […]
Neuropsychological performance 10 years after immunization in infancy with thimerosal-containing vaccinesPublished January 1, 2009 in Pediatrics, Tozzi AE, Bisiacchi P, Tarantino V, De Mei B, D'Elia L, Chariotti F, Salmaso S.
Thimerosal, a mercury compound used as a preservative in vaccines administered during infancy, has been suspected to affect neuropsychological development. We compared the neuropsychological performance, 10 years after vaccination, of 2 groups of children exposed randomly to different amounts of thimerosal through immunization. Children who were enrolled in an efficacy trial of pertussis vaccines in […]
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 […]
This study compared mortality among Danish citizens with autism spectrum disorders (ASDs) with that of the general population. A clinical cohort of 341 Danish individuals with variants of ASD, previously followed over the period 1960-93, now on average 43 years of age, were updated with respect to mortality and causes of death. Standardized mortality ratios […]
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 […]