Prenatal diagnosis of congenital nephrosis of the Finnish type (CNF) in the second trimester.

Congenital nephrosis of the Finnish type is an hereditary, autosomal recessive disease which leads to death in early infancy. This is a case report concerning an affected fetus with legal interruption in the 24th week of gestation on the basis of certain sonographic changes in the fetal kidneys and changes in the protein profile in amniotic fluid, which were consistent with nephrotic damage of the kidneys. Light and electron microscopy showed evidence of CNF, i.e. increase of mesangial matrix and cells in glomeruli, dilated tubular segments, and effaced and plumb foot-processes of the glomerular epithelial cells. Antenatal diagnosis of CNF therefore seems feasible in the second trimester of gestation by means of AFP determinations in maternal serum and amniotic fluid as well as by using sonographic criteria and determination of proteins in amniotic fluid.