Abstract
Congenital nephrosis of the Finnish type (CN) is an hereditary, autosomal recessive disease which invariably leads to death in early infancy. We have found certain ultrastructural morphologic changes of the same type as in manifest CN to be present in kidney- and placental tissue specimens as early as in the 17th-19th week post last menstrual period (LMP) in two affected fetuses. The placental structures appeared in some respects immature in relation to gestational age. The morphological alterations were found to be associated with renal, and possibly placental functional failure, resulting in extensive elevation of alpha-fetoprotein (AFP) levels in amniotic fluid and maternal serum from the 16th and 12th week post LMP, respectively. Morphological structures of a similar type were absent, or only rarely observed, in eight control fetuses of comparable gestational age. Both mothers who previously had affected children as well as affected fetuses, have now given birth to healthy infants after pregnancies characterized by repeatedly normal levels of AFP in maternal serum and amniotic fluid. Antenatal diagnosis of CN therefore seems feasible between the 12th-19th postmenstrual weeks by means of AFP-determinations in maternal serum and amniotic fluid.