Idiopathic gout, uric acid lithiasis, acute uric acid nephropathy; neoplastic & myeloproliferative disease w/ high cell turnover rates in which high urate levels occur either spontaneously or after cytotoxic therapy; certain enzyme disorders ie, hypoxanthine guanine phosphoribosyltransferase eg, Lesch-Nyhan syndrome; glucose-6-phosphatase eg, glycogen storage disease; phosphoribosylpyrophosphate synthetase & amidotransferase; adenine phosphoribosyltransferase. Management of 2, 8-dihydroxyadenine (2,8-DHA) renal stones related to deficient activity of adenine phosphoribosyltransferase; recurrent mixed Ca oxalate renal stones in the presence of hyperuricosuria, when fluid, dietary & similar measures have failed.