ABCC9 and hypertrichotic osteochondrodysplasia Cantu type: While a contribution of KATP channel dysfunction to the observed pathologies is not well established in most cases, a convincing causal association is seen between gain of function mutations in ABCC9 and KCNJ8 and Cantú syndrome, a pleiotropic developmental disorder including severe cardiovascular defects, hypertrichosis, facial dysmorphy, and macrocephaly.