CNVs at the PTCHD1 locus were initially assessed in 427 ASD patients, as described (3). DNA samples from 900 individuals diagnosed with ASD were sequenced for PTCHD1 mutations. Among these, 400 samples were collected at three sites, namely The Hospital for Sick Children (HSC) in Toronto and child diagnostic centers in Hamilton, Ontario and St, John’s, Newfoundland. Details of these samples are published elsewhere (5). 420 ASD cases were recruited at Montreal, details of these samples are published elsewhere (35). Another 80 ASD probands from the Autism Genetic Resource Exchange (AGRE) were also included. The second cohort of 996 autism probands was recruited at different sites as a part of the Autism Genome Project (AGP); ascertainment is described elsewhere (15). 246 male patients with intellectual disability were recruited from the UK, United States, Australia, Europe and South Africa as the IGOLD study. A subset of 225 from this cohort were also used for sequence analysis of PTCHD1. Details of these samples are published elsewhere (36). 167 unrelated patients diagnosed with ADHD were recruited through the Department of Psychiatry at the
