SMCHD1 and arhinia, choanal atresia, and microphthalmia: Several studies identified missense or nonsense mutations distributed over the entire SMCHD1 locus in FSHD2 but heterozygous missense mutations in the ATPase domain of SMCHD1 are also associated with the rare developmental disorder Bosma Arhinia and Microphtalmia Syndrome (BAMS; MIM603457)39,40.