ARID1B and Coffin-Siris syndrome: The ARID1B gene has been suggested to be associated with the occurrence of Coffin-Siris syndrome [17], a multiple congenital anomaly/mental retardation syndrome characterized by mild to moderate mental retardation, moderate to severe hypotonia, epilepsy, and congenital malformation, including a coarse facial appearance and incompletely formed fifth fingers and toes.