Ataxia and disorders of purine metabolism: defects in hypoxanthine guanine phosphoribosyl transferase and clinical ataxia.

A relationship between disordered metabolism of purines and the central nervous system has been established by the Lesch-Nyhan syndrome. In this disorder a virtually complete defect in the activity of HGPRT is associated with a syndrome of severe mental retardation, choreoathetoid cerebral palsy, and bizarre, self-mutilative behavior. In patients with partial defects in HGPRT, two have had symptoms that have been labeled spinocerebellar. Neither were appreciably ataxic, and the relationship between the symptoms and the enzyme defect remains to be established. Analysis of HGPRT in members of a large kindred with spinocerebellar degeneration revealed normal levels of the enzyme. These observations suggest that a relationship between the activity of HGPRT and clinical ataxia is remote.