KCNJ8 and hypertrichotic osteochondrodysplasia Cantu type: Gain-of-function mutations in KCNJ8 or ABCC9 result in Cantu syndrome, a rare genetic disorder characterized by excessive hair growth, distinctive facial features, and an enlarged heart (Harakalova et al., 2012; van Bon et al., 2012; Brownstein et al., 2013; Li et al., 2013; Nichols et al., 2013; Cooper et al., 2014).