A MISSENSE MUTATION IN THE HYPOXANTHINE PHOSPHORIBOSYLTRANSFERASE GENE IN A PEDIATRIC-PATIENT WITH HYPERURICEMIA

We have identified a mutation in the gene coding for the enzyme hypoxa nthine phosphoribosyltransferase in a pediatric patient with hyperuric emia and nephrolithiasis. The mutation is a nucleotide substitution ca using an amino acid substitution in the hypoxanthine phosphoribosyltra nsferase protein. In this patient, fibroblasts but not lymphocytes sho wed resistance to 6-thioguanine, and reduced enzyme activity was detec ted in lymphocytes. These results are consistent with the intermediary phenotype associated with partial hypoxanthine phosphoribosyltransfer ase enzyme deficiency. Altogether, six males in this family suffered f rom hyperuricemic symptoms, and small differences in phenotype were se en.