Lesch-Nyhan variant syndrome: real-time rt-PCR for mRNA quantification in variable presentation in three affected family members.

Inherited mutations of hypoxanthine guanine phosphoribosyltransferase (HPRT) give rise to Lesch-Nyhan syndrome (LNS) or variants (LNV). We report molecular insights from real-time RT-PCR for HPRT mRNA quantification into the mechanism by which a single mutation located in exon 7 of the HPRT gene: c.500G>T, p.R167M, led to different clinical phenotypes from three male LNV-affected patients in the same family manifesting parallel differences in enzymatic activities. This approach can be applied for understanding genotype-phenotype correlations for other human genetic diseases.