Carrier and prenatal diagnosis of Lesch-Nyhan disease due to a defect in HPRT gene expression regulation.

Lesch-Nyhan disease (LND) is caused by lack of hypoxanthine-guanine phosphoribosyltransferase (HPRT) activity. Mutations in HPRT1 gene show variability in type and location within the gene, and in certain patients the HPRT coding sequence is normal and the molecular defect cannot be found. These patients presented a decreased HPRT1 expression of unknown cause. This is the first report of a carrier and prenatal diagnosis of LND due to a defect in HPRT gene expression regulation.