AHDC1 and obstructive sleep apnea syndrome: And AHDC1 is nearby AT-rich interaction domain 1A (ARID1A) gene, mutations in which cause autosomal-dominant Coffin-Siris syndrome, and its symptoms are maxillary hypoplasia, tongue cleft, poor alignment of teeth, etc. OSA could coexist with spinocerebellar ataxia type 1, which is a hereditary disease of the nervous system regulated by AHDC1. Abnormalities of AHDC1 probably cause pharyngeal dilator muscle incoordination, thereby leading to airway collapse [9, 18, 19].