Uromodulin gene (UMOD) mutations have been confirmed in patients with familial juvenile hyperuricemia nephropathy (FJHN, OMIM 162000), medullary cystic kidney disease 2 (MCKD2, OMIM 603860) and glomerulocystic kidney disease (GCKD, OMIM 609886). The gene discussed is UMOD; the disease is autosomal dominant medullary cystic kidney disease with or without hyperuricemia.