A novel mutation in a patient with familial renal hypouricemia type 2

Introduction: Hypouricemia may be caused by disorders leading to decreased UA production, oxidation of UA to allantoin by drugs or increased renal tubular loss of filtered UA, renal hypouricemia (RHUC). RHUC may be resulted from familial or acquired disorders. Familial RHUC cases are classified according to the gene affected as type 1 (SLC22A12 gene) and type 2 (SLC2A9). Clinical importance of RHUC entity is mainly determined by emerging of acute kidney injury (AKI) after strenuous exercise and urolithiasis. Case presentation: Here, we report a case of RHUC with increased fractional excretion of uric acid value of more than 100%, serum uric acid level of nearly zero, and exercise-induced AKI episodes clinically and a new unpublished homozygous (biallelic) mutation of c.1419+2T>G (IVS11+2T>G) in the SLC2A9 gene genetically for the first time to our knowledge. Conclusion: Clinicians should be aware of this rare entity defined as hereditary RHUC in order to provide long term renoprotection by advisements like simple precautions such as avoiding severe exercises. (C) 2021 Sociedad Espanola de Nefrologia. Published by Elsevier Espana, S.L.U.