[Lesch-Nyhan disease studied in intact fibroblasts]

A 5 year old spanish boy was studied in whom the clinical phenotype was that of classic Lesch-Nyhan syndrome. Activity of hypoxanthine guanine phosphoribosyl transferase (HGPRT) was studied in an intact fibroblast system in which the pattern of incorporation of isotope of 14C-labeled hypoxanthine into its purine products was assessed. This method has been effective in distinguishing among HGPRT variants even when activity in erythrocyte lysates is zero. In this patient the activity was 0,4 percent of normal, consistent with Lesch-Nyhan disease.