ABSTRACT
Impaired motor development, spastic cerebral palsy, involuntary movements; self-injurious behavior; hyperuricemia, uricosuria, urinary tract calculi, nephropathy, tophi, gouty arthritis; and deficient activity of hypoxanthine guanine phosphoribosyl transferase (HPRT). In variants, hyperuricemia, gout, or renal calculi; in a neurologic variant, the phenotype is identical to that of Lesch–Nyhan disease, but self-mutilation is absent and intelligence may be normal; in another variant, the expression is of dystonia mimicking spastic diplegia and mildly impaired mental development. Variant HPRT enzymes may have activity that is 0 or as much as 50 percent of normal in hemolysates, but over 1.4 percent of control in the intact cell assay.
