Haploinsufficiency of MeCP2-interacting transcriptional co-repressor SIN3A causes mild intellectual disability by affecting the development of cortical integrity

Sharon Kolk, Tjitske Kleefstra and colleagues identify loss-of-function mutations in SIN3A in individuals with intellectual disability and other clinical features. They further show that knockdown of Sin3a in developing mouse brain results in reduced cortical neurogenesis, altered neuronal identity and aberrant cortical projections, identifying this MeCP2-interacting protein as a key regulator of cortical development.