Recent estimates suggest that SYNGAP1-ID may represent one of the most common monogenic forms of intellectual disability (Hamdan et al., 2009; Berryer et al., 2013, 2016; Parker et al., 2015), therefore making SYNGAP1 haploinsufficiency one of the most frequent causes of genetically defined childhood brain disorders. This evidence concerns the gene SYNGAP1 and brain disorder.