The goal of the proposed research is to examine the range of behavioral and cognitive profiles associated with strongly predisposing, rare genetic events for autism. Rare protein trucating variants have been associated with these conditions in clinical ASD populations, and we would like to complement the case-control findings with a general population consideration of their effects. This gene-first approach would aid in elucidating the nature of the noted risk relationships, most specifically the penetrance and phenotypic range of rare variant influence.