Antenatal genetic screening for congenital nephrosis

This study was undertaken to study the applicability of genetic antenatal s creening for the Finnish type of congenital nephrosis (CNF), which is a rec essive disorder leading to nephrotic syndrome from birth. At Kuopio Univers ity Hospital, a total of 1303 pregnant women were offered carrier screening for CNF at the time of first trimester nuchal fold translucency measuremen t when fetally derived alpha-fetoprotein is still produced by the yolk sac. Two mutations of the nephrin (NPHS 1) gene, accounting for approximately 9 5% of affected alleles, were tested by two PCR tests. Uptake of the gene te st was 91.0% (n = 1183). Altogether 38 female carriers were found; a popula tion carrier frequency of 1 in 31. Their partners were tested and two of th em were also found to be carriers. In these two pregnancies invasive prenat al diagnosis was offered and accepted, and the results indicated one carrie r and one affected fetus. Carrier screening is an effective and well-accept ed method for antenatal screening for fetal CNF. Direct mutation analysis i nvolves markedly less invasive procedures compared with serum alpha-fetopro tein (AFP) screening, and the diagnosis was clearcut. The results indicate that in single-gene disorders genetic testing is suitable for antenatal scr eening. Copyright (C) 2001 John Wiley & Sons, Ltd.