SHANK3 and Phelan-McDermid syndrome: In family 7, four affected individuals were found to have a splice acceptor site deletion variant (c.1305-3_1,305-2delTT; p.Gln29_Gly305del) in the SHANK3 gene (NM_001372044.2), which is associated with Phelan-McDermid syndrome (OMIM 606232).