The role of rare structural variants in the genetics of autism spectrum disorders.

Autism is a neurodevelopmental disorder characterized by impaired social interaction and communication and restricted interests and behaviors. Despite high estimates of heritability, genetic causes of ASD have long been elusive, due in part to a high degree of genetic and phenotypic heterogeneity (Bailey et al., 1995). Recently, important advances have been made in the genetics of ASD with the use of new technologies for the direct detection of copy number variation (CNV) in the human genome. CNV studies have revealed that de novo deletions and duplications, typically less than 1 Mb in size, are strongly associated with ASD, suggesting that spontaneous structural mutations play a more important role in the etiology of disease than was previously recognized. Rare mutations have been identified at many different locations in the genome, and multiple 'hot spots' have been identified where identical rearrangements recur with high frequency. These findings are consistent with the hypothesis that autism, like mental retardation, is caused by a large number of individually rare mutations. These studies serve as a model for how other emerging technologies for mutation detection (e.g. next generation sequencing platforms) could be used to further elucidate the role of rare sequence changes in ASD. Copyright 2009 S. Karger AG, Basel.