The Simons Foundation has funded five university-based medical centers to identify and study a large number of individuals (~200 families within two years) with a recurrent genetic variation (deletion or duplication of segment 16p11.2) that increases their risk of developing autism spectrum and other neuro­developmental disorders. The immediate goal is to identify medical, cognitive, neural and behavioral profiles shared by this genetically identified group. Families are recruited through web-based networks or referral by clinical genetic centers or testing laboratories. Extensive psychological and neurological testing and neuroimaging with a uniform protocol will take place at the collaborating medical centers.