Prenatal diagnosis by enzyme analysis in 15 pregnancies at risk for the Lesch-Nyhan syndrome.

Fifteen pregnancies at risk for Lesch-Nyhan syndrome were investigated between 8 and 17 weeks' gestation by measurement of hypoxanthine-guanine phosphoribosyl transferase (HGPRT) and adenine phosphoribosyl transferase (APRT) enzyme activities in chorionic villus samples (cultured and uncultured) or in cultured amniotic fluid cells. Ten pregnancies had normal enzyme levels and a normal outcome while a further two predicted to be normal miscarried later in the pregnancy. Three pregnancies had low levels of residual HGPRT activity in chorionic villi. Comparable levels of residual activity in the index case in two pregnancies and in cells from the abortus in the third case confirmed that the pregnancies were affected.