Prenatal Diagnosis of Lesch-Nyhan Syndrome by Purine Analysis of Amniotic Fluid and Cordocentesis

Abstract

Lesch-Nyhan syndrome is an X-linked disorder caused by a deficiency of the enzyme hypoxanthine guanine phosphoribosyltranferase (HGPRT, E.C.2.4.2.8) that catalyzes the conversion of hypoxanthine and guanine to their respective nucleotides (1,2). Lack of this enzymatic activity promotes an increase of hypoxanthine, xanthine and uric acid in biological fluids and an enhancement of adenine phosphoribosiltransferase (APRT, E.C.2.4.2.7) in cells (2). Because of Lesch-Nyhan syndrome (LNS) severity, early prenatal diagnosis may be requested to provide genetic advice. The prenatal diagnosis of LNS has been performed by enzyme assay or DNA analysis in amniocytes or chorionic villus sampling (3,4). Cordocentesis permits the obtaining of fetal blood for enzyme assay although its usefulness in the antenatal diagnosis of LNS has not been reported. Furthermore, there are no studies on the concentration of oxypurines in amniotic fluid in pregnancies with fetuses at risk of LNS. In this study we made a prenatal diagnosis of the LNS by cordocentesis in the 21st gestational week. In addition, we report the results of oxypurine levels in amniotic fluid.