[Prenatal differential diagnosis in elevated alpha-fetoprotein concentration in the amniotic fluid (author's transl)].

Elevated Alpha-Fetoprotein (AFP) values in the amniotic fluid are most frequently associated with neural occlusive disturbances or, in rare cases, with other external malformations of the foetus. In this article, the authors report on two cases where the elevated AFP had not been due to fetal malformations. In the first case, the cause was identified as foetal proteinuria, probably in the sense of an autosomal-recessive hereditary congenital nephrosis, whereas in the second case the phenomenon was possibly due to a "foetal distress" syndrome. Attention is drawn to the importance of elevated AFP levels. The possibilities of further prenatal differential diagnosis are discussed, such as ultrasound, determination of acetyl cholinesterase AChE) activity and assessment of the amniotic fluid cells.