Cantú syndrome (CS) is a rare genetic autosomal dominant disorder caused by dominant gain-of-function mutations in the ATP-dependent potassium (KATP) channel genes ABCC9 (Harakalova et al., 2012; Van Bon et al., 2012) and KCNJ8 (Brownstein et al., 2013; Cooper et al., 2014, 2017), encoding sulfonylurea receptor 2 SUR2 and inward rectifier potassium channel 6.1 Kir6.1, respectively. The gene discussed is KCNJ8; the disease is Cowden syndrome 1.