Familial juvenile hyperuricemic nephropathy (FJHN) is an autosomal-dominant disease characterized by hyperuricemia of underexcretion type, gout, and chronic renal failure. Recent discovery of uromodulin mutations as a cause of FJHN and MCKD2 led a new concept, i.e. uromodulin-associated kidney disease (UAKD). The genotype-phenotype correlation and genetic heterogeneity of FJHN are reviewed.