The Autism Genetic Resource Exchange (AGRE) curates a collection of DNA and phenotypic data from multiplex families with autism spectrum disorder (ASD) available for genetic research 3. We genotyped individuals from 801 families, selecting those with at least one child meeting criteria for autism by the Autism Diagnostic Interview-Revised (ADI-R) 25, while the second affected child had an AGRE classification of autism, broad spectrum (patterns of impairment along the spectrum of pervasive developmental disorders, including PDD-NOS and Asperger syndrome) or Not Quite Autism (NQA, individuals who are no more than one point away from meeting autism criteria on any or all of the social, communication, and/or behavior domains and meet criteria for “age of onset”; or, individuals who meet criteria on all domains, but do not meet criteria for the “age of onset”). We excluded probands with widely discrepant classifications of affection status via the ADI-R and ADOS that could not be reconciled. We also excluded families with known chromosomal abnormalities (where karyotyping was available), and those with inconsistencies in genetic data (generating excess Mendelian segregation errors or showing genotyping
