HPRT1 and hyperinsulinemic hypoglycemia, familial, 4: We recently proposed that the treatment of severe early onset hyperuricemia, as observed in hereditary hypoxanthine-guanine phosphoribosyltransferase (HPRT)-deficiency and Lesch-Nyhan disease (LND), could be approached by facilitating rather than blocking the purine degradation pathway (uricolytic versus uricostatic approach).