Abstract Background: Familial juvenile hyperuricemic nephropathy (FJHN) is a rare autosomal dominant disease characterized by hyperuricemia, gout, and chronic renal failure. The UMOD variants are the most common genetic cause of FJHN. Case presentation: We report a novel heterozygous pathogenic UMOD mutations c. 296 G>A (p. Arg99His) in a 5-year-old boy who presented with hyperuricemia and gouty arthritis. This UMOD mutation was also carried by the proband’s elder sister, father, uncle, cousin and grandfather, who had similar clinical signs. The family members were treated with allopurinol and controlled diet to maintain the serum uric acid levels. None of them developed end stage renal disease. The mutation segregated in the family and was the cause of the disease in the proband. c. 296 G>A (p. Arg99His) mutation was not described in the ExaC, GNomAD and 1000 Genomes Project databases. The mutated amino acids were located in a highly conserved region of the UMOD protein. This mutation was predicted to be damaging and deleterious. A phenotype-genotype correlation analysis of UMOD variants was consistent with those clinical signs. Conclusions: Our finding suggest that genetic test for specific mutation in UMOD gene should be included in the diagnosis for patients with hyperuricemia, gout, or unexplained chronic kidney disease. Keywords: Hyperuricemia; Gout; UMOD; Mutation; China Abbreviations: FJHN: Familial juvenile hyperuricemic nephropathy; ACMG: American College of Medical Genetics; eGFR: estimated glomerular filtration rate; EGF: epidermal growth factor.