Partial HPRT deficiency (Kelley-Seegmiller syndrome).

Hypoxanthine-guanine phosphoribosyl transferase (HPRT) deficiency is an X-linked defect of purine metabolism. Clinical manifestations are usually related to the degree of enzyme deficiency; complete HPRT deficiency (Lesh-Nyhan Syndrome) presenting with severe neurological or renal symptoms, or partial HPRT deficiency (Kelley-Seegmiller syndrome) manifesting as a gout-urolithiasis syndrome. We report a case of partial HPRT deficiency presenting as chronic tophaceous gout, mental retardation, nephrolithiasis and family history suggestive of X-linked inheritance, for its rarity.