As the disease is recessively inherited, sequencing of HADH is recommended in all patients with diazoxide-responsive CHH, following exclusion of mutations in ABCC8/KCNJ11 genes (1,5), who originate from known consanguineous pedigrees, isolated populations or countries where inbreeding is frequent. The gene discussed is KCNJ11; the disease is cartilage-hair hypoplasia.