Biomarkers

Simple Worms could Help Unravel Complex Human Brains

Source: 
Simons Foundation Austism Research Initiative
Date Published: 
July 25, 2012
Abstract: 

The nematode "Caenorhabditis elegans" may serve as a useful model to study synapses, the junctions between neurons.

Cognition and behavior: Fragile X Carriers Show Autism Signs

Source: 
Simons Foundation Austism Research Initiative
Date Published: 
July 27,2012
Abstract: 

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.

Vanderbilt University Researchers Examine Oxytocin and Serotonin Systems as Biomarkers for Autism

Source: 
http://www.ncbi.nlm.nih.gov/pubmed/22721594.1
Date Published: 
May 26, 2012
Abstract: 

Vanderbilt University researchers examine oxytocin and serotonin systems as biomarkers for autism spectrum disorders.

Newly Published Genetics/Brain Tissue Study Will Help Refine the Search for Specific Early Genetic Markers of Risk of Autism in Babies and Toddlers

Source: 
PLoS Genetics
Date Published: 
March 22, 2012
Year Published: 
2012
Abstract: 

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 cortex—is 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.

By Dr. Eric Courchesne

A new study of autism published today in PLoS Genetics (Age Dependent Brain Gene Expression and Copy Number Anomalies in Autism Suggest Distinct Pathological Processes at Young Versus Mature Ages) 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 cortex—is 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.

The research is one of the first to focus on gene activity inside the young autistic brain, and is the first to examine how gene expression activity changes across the lifespan in autism.  It is also one of the largest postmortem studies of autism to date. This close-up look inside the brain uncovered the presence of abnormal levels of activity in genes (“gene expression”) and gene defects (deletions of portions of DNA sequences) that control the number of brain cells and their growth and pattern of organization in the developing prefrontal cortex. The abnormal gene activity occurred in several networks that are important during prenatal brain development (cell cycle, neurogenesis, DNA damage detection and response, apoptosis and survival networks). This seems to rule out a number of current speculations about postnatal causes of autism and, combined with the new evidence of a 67% excess of prefrontal brain cells, points instead to prenatal causal events in a majority of cases.

The study’s direct examination of both mRNA and DNA from the same frontal cortex region in each individual is also a unique approach to discovering the genetics of abnormal brain development in autism.  The combined mRNA and DNA results indicate that a large and heterogeneous array of gene and gene expression defects disrupt prenatal processes that are critical to early prefrontal cortex formation. “Although DNA defects vary from autistic case to case, the diverse genetic deletions seem to underlie a relatively common biological theme, hitting a shared set of gene pathways that impact cell cycle, DNA damage detection and repair, migration, neural patterning and cell differentiation,” according to the study.  Importantly, the set of functional gene pathways identified by the study’s direct analyses of autistic brain tissue are consistent with those identified by previous studies that analyzed copy number variations in living autistic patients.

A second major discovery in this study is that the pattern of abnormal gene activity changes across the lifespan in autism. Thus, in adults with autism, the study found abnormal activity in genes involved in remodeling, repair, immune response and signaling. This raises opportunities for new research directions that ask whether and how such later alterations in genetic activity impact brain structure and function.  A hope is that perhaps this later, second stage of unusual genetic activity we detected in adults with autism has something to do with enhancing adaptive connections and pruning back earlier maladaptive connections.  Further research needs to better understand the impact of those later changes in genetic activity.

Findings in the new study will help refine the search for specific early genetic markers of risk of autism in babies and toddlers.  Next steps include identifying what causes the altered genetic activity at early stages of development, when nerve cells in prefrontal cortex arise and the first steps in creating brain circuitry are being taken.  Knowledge of these specific patterns of abnormal gene activity may also give rise to future studies that search for medical interventions that target abnormal gene activity in an age-specific fashion.

Mouse Model Provides Clues to Autism

Source: 
PsychCentral
Date Published: 
March 22, 2012
Abstract: 

Vanderbilt scientists report that a disruption in serotonin transmission in the brain may be a contributing factor for autism spectrum disorder (ASD) and other behavioral conditions.

New Autism Research Reveals Brain Differences at 6 Months in Infants Who Develop Autism

Source: 
Center for Autism Research at The Children's Hospital of Philadelphia (CHOP)
Date Published: 
February 17, 2012
Abstract: 

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.

Both Maternal and Paternal Age Linked to Autism

Source: 
Science Daily
Date Published: 
February 10, 2012
Abstract: 

Older maternal and paternal age are jointly associated with having a child with autism, according to a recently published study led by researchers at The University of Texas Health Science Center at Houston (UTHealth).

Gastrointestinal Problems In Autistic Children May Be Due To Gut Bacteria

Source: 
Medical News Today
Date Published: 
January 11, 2012
Abstract: 

The underlying reason autism is often associated with gastrointestinal problems is an unknown, but new results to be published in the online journal mBio® on January 10 reveal that the guts of autistic children differ from other children in at least one important way: many children with autism harbor a type of bacteria in their guts that non-autistic children do not.

2 Genes Affect Anxiety, Behavior In Mice With Too Much MeCP2

Source: 
Medical News Today
Date Published: 
January 11, 2012
Abstract: 

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.

Autism may be linked to abnormal immune system characteristics and novel protein fragment

Source: 
MedicalXpress
Date Published: 
January 3, 2012
Abstract: 

Immune system abnormalities that mimic those seen with autism spectrum disorders have been linked to the amyloid precursor protein (APP), reports a research team from the University of South Florida's Department of Psychiatry and the Silver Child Development Center.