SYNGAP1 and Oppositional defiant disorder: Rates of ADHD (SYNGAP1-ID n = 2; 15.3%; ID-comparison n = 4; 15.3%; p = 1) and oppositional defiant disorder (SYNGAP1-ID n = 1; 7.7%; ID-comparison n = 0; p = 0.15) were not different across groups.