Genome-wide association studies and neurodevelopment

Autism spectrum disorders (ASDs) are developmental neuropsychiatric conditions affecting communication skills and social interactions with an onset prior to 3 years of age and a 4:1 male-to-female ratio. The current estimate of male prevalence is 1/37. Consensus indicates ASDs are genetically complex and polygenic, with as many as 1000 predisposing genes. Robust detection of these common risk genes is contingent upon continuing development of large study samples that enable a well-powered genome-wide association study (GWAS). A GWAS tests the genome in an unbiased fashion for chromosome regions and genes likely to harbor risk alleles. A recent GWAS meta-analysis of approximately 45,000 Danes identified five genetic loci for ASDs, a marked improvement over previous studies. Using rigorous criteria, a search for concordance in bioinformatics databases implicated GRIN2A, MACROD2, and PHB as likely risk genes for ASDs and their related traits. Improving technologies and increasing samples will provide a greater understanding of the etiologies of ASDs.