The genomes of the largest collection of families with multiple cases of autism ever assembled have been scanned in a new study. The results provide new insights into the genetic basis of autism, according to a report published online in Nature Genetics.
Autism spectrum disorders (ASD) influence social interaction and communication and affect 6 out of every 1,000 children. The Autism Genome Project Consortium -- comprising 50 centers in North America and Europe -- collected DNA samples from nearly 1,500 families, each of which has more than two members with ASD.
The team carried out a two-fold analysis. First they assessed the frequency of alterations in copy number of different segments of the genome, finding an unexpectedly high percentage of the families -- 7 to 12%, depending on how the analysis was done -- in which all affected individuals share possibly detrimental chromosomal abnormalities. Two female siblings had deletions of the gene encoding the protein neurexin 1, which interacts with neuroligins -- a family of proteins that have been implicated in some cases of autism. Finally, the authors carried out a 'linkage' analysis of these families, searching for regions of the genome that might be shared by the individuals with ASD. One particular region on chromosome 11 was identified, which has not previously been reported to harbour genes that affect risk of developing autism.
Bernie Devlin (University of Pittsburgh, PA, USA)
Stephen Scherer (The Hospital for Sick Children and University of Toronto, ON, Canada)
Abstract available online.
(C) Nature Genetics press release.
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