Lesch-Nyhan Phenotype With Normal Hgprt

Nyhan et al. (1978) described a male patient with self-mutilation, mental retardation, choreoathetosis, spasticity and hyperuricemia, identical to the clinical picture of HGPRT deficiency (308000). Although HGPRT and purine salvage were normal, an abnormality in synthesis or catabolism of trinucleotides was suggested by an unusual accumulation of trinucleotides. Nyhan (1989) stated that since subsequent studies of cells from this patient failed to show consistent accumulation of trinucleotides, there is no real evidence of abnormality in purine metabolism. He reiterated that 'the phenotype was absolutely typical.'