ARID1B is the most commonly mutated gene in Coffin-Siris syndrome (CSS), a monogenic syndrome characterized by growth retardation, facial dysmorphism, and intellectual disability (ID) (Santen et al., 2012; Tsurusaki et al., 2012; Wieczorek et al., 2013). This evidence concerns the gene ARID1B and Coffin-Siris syndrome.