To more comprehensively test the common variant hypothesis, we performed an unbiased genome-wide association study of common variation using as a discovery dataset the Caucasian autistic families from the Collaborative Autism Project (CAP). We validated our findings using an independent publicly available family-based Genome-Wide Association Study (GWAS) dataset from the Autism Genome Research Exchange (AGRE) (Autism Genetics Resource Exchange 2008). Quality-control (QC) procedures were applied to the more than 1,000,000 single nucleotide polymorphisms (SNPs) in the discovery dataset and 550,000 SNPs in the validation dataset.
