Prenatal diagnosis of congenital nephrosis in 23 high-risk families.

The efficacy of maternal serum and amniotic fluid alpha-fetoprotein (AFP) estimation for the prenatal detection of congenital nephrosis was assessed in 23 pregnancies of couples with a previously affected child. At 15 to 18 weeks' gestation, amniotic fluid AFP concentration was elevated in seven of 23 cases, and maternal serum AFP level in five of these. Legal abortion was carried out at 18 to 19 weeks in all those cases where he amniotic fluid AFP concentration was abnormally high, and in all cases the fetus was found to be affected. The diagnosis of intrauterine congenital nephrosis was obvious by electron microscopic examination of the fetal kidney, but not by light microscopy. The child was born without congenital nephrosis in all 16 cases where amniotic fluid AFP level was normal, and in 16 of 18 cases (89%) where maternal serum AFP concentration was normal. Thus, the amniotic fluid AFP assay is more reliable and is recommended whenever congenital nephrosis is suspected on the basis of family history.