A NOVEL DE-NOVO MUTATION IN HPRT GENE RESPONSIBLE FOR LESCH-NYHAN SYNDROME (HPRT(OSAKA))

A virtually complete deficiency of hypoxanthine guanine phosphoribosyl transferase (HPRT) causes Lesch-Nyhan syndrome. A novel mutation of HP RT gene in a Japanese Lesch-Nyhan family has been identified using mRN A and genomic DNA from peripheral blood cells. A single nucleotide sub stitution of T to C in exon 3 resulted in a mis-sense mutation, CTC (L eu) to CCC (Pro), at codon 65. Utilizing an Mn/I restriction site whic h was lost in the mutation as an indicator, a family study showed that the mother was normal not having the mutant gene. The mutation was a de novo event that had occurred in the germ cells of the mother or in the proband during the early phase of fetal development.