Urinary guanidinoacetate and creatine levels in patients with HPRT deficiency.

Neurobehavioral manifestations of complete HPRT deficiency include severe action dystonia, choreathetosis, alteration of executive functions, and self-injurious behavior. Dystonic manifestations are also present in patients with partial HPRT deficiency. Pathophysiology of these manifestations is unknown. Guanidinoacetate is a neurotoxin implicated in certain dystonic syndromes. We have examined guanidinoacetate and creatine levels in urine from 11 HPRT deficient patients (9 with Lesch-Nyhan syndrome and 2 with partial deficiency). Urinary guanidinoacetate and creatine levels in HPRT deficient patients were within the normal range. Guanidinoactetate alteration does not seem to be implicated in the pathogenesis of the neurological disease associated with HPRT deficiency.