Genetics

Multiple Recurrent De Novo CNVs, including Duplications of the 7q11.23 Williams Syndrome Region, are Strongly Associated with Autism

Source: 
Pediatrics
Date Published: 
May 2011
Year Published: 
2011

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 autism risk. Using gene chip or microarray technology, the researchers analyzed the genomes of over 1,100 families with a single child on the autism spectrum, and compared the results of affected and unaffected siblings. The DNA samples analyzed in the study were part of the Simons Simplex Collection. The scan revealed a variety of copy number variants (CNVs) -- genetic mutations that can range from micro-deletions and duplications to large sequences of missing or additional DNA. Notably, one of the non-inherited or de novo CNVs was located on a genetic region linked to Williams-Beuren syndrome, a rare disorder that causes people to be extremely social, overly trusting, and highly empathetic.While loss of DNA from the area results in Williams-Beuren syndrome, gain of extra DNA in this area is associated with autism, which is marked by difficulty with social interaction and lack of empathy. This region's connection with both disorders suggests its importance in understanding the nature of the social brain. The study also supports earlier findings of higher rates of de novo CNVs in people with autism compared to their unaffected siblings. Uncovering the genetic basis of autism is critical to understanding the neurobiology underlying the disorder and may aid in developing targeted treatment approaches for different subtypes.

--IACC 2011 Summary of Advances in ASD Research

Researchers Reveal 18 Novel Subtype-Dependent Genetic Variants for Autism Spectrum Disorders and Identify Potential Genetic Markers for Diagnostic Screening

Source: 
Science Daily
Date Published: 
April 28, 2011
Abstract: 

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.

Autism Spectrum Disorder Linked to Genetic Synaptic Behaviors

Source: 
Medical News Today
Date Published: 
April 21, 2011
Abstract: 

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.

Atlas Gives Scientists New View of the Brain

Source: 
The Wall Street Journal
Date Published: 
April 13, 2011
Abstract: 

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.

Common Genetic Cause of Autism and Epilepsy Discovered

Source: 
Science Daily
Date Published: 
April 8, 2011
Abstract: 

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.

Gene Linked to Severity of Autism's Social Dysfunction Identified

Source: 
Science Daily
Date Published: 
April 7, 2011
Abstract: 

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.

A Genotype Resource for Postmortem Brain Samples from the Autism Tissue Program

Source: 
Autism Res, Wintle et al.
Date Published: 
April 2011
Year Published: 
2011

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 genotype/phenotype verification. In this study, scientists from the Hospital for Sick Children in Toronto verify the ethnicity and gender of a certain sample, and provide an algorithmic verification system for other researchers looking to provide accurate research into the genotype/phenotype makeup of their sample.

MIT Researchers Recreate Autism in Mice

Source: 
Medical News Today
Date Published: 
March 20, 2011
Abstract: 

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.

Gene Variants in Autism Linked to Brain Development

Source: 
Science Daily
Date Published: 
March 7, 2011
Abstract: 

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.

Gene Variants in Autism Linked to Brain Development

Source: 
Journal of Molecular Psychiatry, Gai et al.
Date Published: 
March 2011
Year Published: 
2011

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 gene alterations are individually very rare, they mostly appear to disrupt genes that play important functional roles in brain development and nerve signaling. While an association between genomic variants in certain nervous system processes and autism has been hypothesized in the past, this research definitively links these biological functions to autism. 

"This large study is the first to demonstrate a statistically significant connection between genomic variants in autism and both synaptic function and neurotransmission," said senior author Peter S. White, Ph.D., a molecular geneticist and director of the Center for Biomedical Informatics at The Children's Hospital of Philadelphia. Synapses are the contact points at which nerve cells communicate with other nerve cells, while neurotransmitters are the chemical messengers carrying those signals.

"Prior genomic studies of autism have successfully identified several genes that appear to confer risk for autism, but each gene appears to contribute to only a small percentage of cases," said the lead author, Xiaowu Gai, Ph.D. "Our approach considered whether groups of genes with common biological functions collectively accounted for a greater percentage of autism risk."

-- via Science Daily http://www.sciencedaily.com/releases/2011/03/110301111243.htm.