Background. Familial juvenile hyperuricemic nephropathy (FJHN) is a genetic disorder with the autosomal dominant mode of hereditability; characterized with hyperuricemia, gout and progressive renal disease. Characterization of the disease together with clinical and biochemical findings in patients of Czech population is described. Methods and Results. The bloodlines of three Czech families with FJHN were set up on the basis of their family history. The specimens of blood and urine were taken from 57 family members for biochemical investigations and isolations of genomic DNA. Blood and urinary concentrations of the uric acid and creatinine together with values of excretion fraction of uric acid and Kaufman’s index were determined. Based on these results diagnosis of FJHN was established or confirmed in 19 patients. One additional patient was diagnosed on the results of linkage analysis. Conclusions. FJHN is a disorder sharing non-specific clinical and biochemical signs with the group of familial renal disorders. The effective diagnosis is difficult due to the heterogeneity of the disorder and limited availability of molecular genetic analysis. Detailed purine metabolic investigation together with precise family history is thus necessary and very important in family members with hyperuricemia and/or gout (particularly in childhood or young women) as well as in patients with familial renal disease.

        Key words: familial juvenile hyperuricemic nephropathy, hyperuricemia, gout, renal failure, excretion fraction of uric acid, uromodulin.