ABSTRACT
Male infants with the P. Lesch–W. L. Nyhan disease appear normal at birth and usually develop normally for the first six to eight months. 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. Lesch–Nyhan patients do not have sensory abnormalities; they scream in pain when they bite themselves and cry in terror of its anticipation. The discovery of the enzyme defect in Lesch–Nyhan disease was followed shortly by the recognition of deficiency of the enzyme in patients with gout or urinary tract calculi. In contrast to the mutations in the classic Lesch–Nyhan disease, the majority of the variants had missense mutations.
