We have found a Czech family with renal hypouricemia caused by a homozygous insertion in the SLC2A9 gene with no sequence variants in SLC22A12, SLC17A3, ABCC4 or ABCG2. Homozygous loss-of-function mutations in SLC2A9 cause massive renal hypouricemia via total loss of uric acid absorption, however, they do not necessarily lead to nephrolithiasis and acute kidney injury.
Our finding of a defect in the SLC2A9 gene shows the following: a) it provides further evidence that SLC2A9 is a causative gene in renal hypouricemia type 2 with clinical distinctions; b) it supports the prediction that normal function of both URAT1 and GLUT9 are essential for normal uric acid reabsorption in the renal proximal tubule.