ARID1B and Coffin-Siris syndrome 1: In 2012, both heterozygous deletions and point mutations in the switch/sucrose non-fermentable SWI/SNF-like chromatin remodeling complex gene ARID1B were reported to cause CSS1 in a monoallelic, autosomal dominant trait inheritance, Mendelian model (Hoyer et al., 2012; Santen et al., 2012).