SLC22A12 and hyperuricemia: Less common causes include primary hyperuricemia due to hypoxanthine-guanine phosphoribosyltransferase deficiency (Lesch–Nyhan syndrome) or hyperuricemia due to decreased urate reabsorption in the proximal tubules; the latter can occur during exercise in patients with acute Fanconi-like syndrome or in patients with familial renal hypouricemia due to deficiency of URAT1 activity.