SHANK3 and Phelan-McDermid syndrome: In our most compelling finding, we identified a mutational ‘hotspot’ in a string of 8-Gs in exon 21 (p.Ala1227Glyfs*69) of the SHANK3 gene that was present in 17 individuals from 15 unrelated families with ASD, as well as one individual with several autistic features and Phelan-McDermid Syndrome (but who was not tested for ASD).