Pathogenic variation in SYNGAP1, the gene encoding SynGAP proteins, is a leading cause of sporadic neurodevelopmental disorders (NDDs) defined by impaired cognitive function, seizure, autistic features, and challenging behaviors (Deciphering Developmental Disorders Study, 2015; Deciphering Developmental Disorders Study, 2017; Hamdan et al., 2009; Vlaskamp et al., 2019; Parker et al., 2015; Mignot et al., 2016; Iossifov et al., 2014; Satterstrom et al., 2020). The gene discussed is SYNGAP1; the disease is cognition.