Severe phosphoribosylpyrophosphate synthetase superactivity

A severe form of phosphoribosylpyrophosphate (PRPP) synthetase superactivity, an X-linked disorder of purine metabolism, characterized by early onset hyperuricemia and hyperuricosuria, and clinically manifesting with urolithiasis, gout and neurodevelopmental anomalies consisting of variable combinations of sensorineural hearing loss, hypotonia, and ataxia.