Amniotic fluid alpha-fetoprotein elevation with fetal omphalocele and a possible mechanism for its occurrence.

Prenatal diagnosis of genetic disease and congenital malformations has become a major area of study in obstetrics. The assessment of amniotic fluid alpha-fetoprotein (AFP) is useful for the diagnosis of neural tube defects. As more patients have been evaluated abnormal increases have been found in other defects, such as omphalocele, duodenal atresia, and congenital nephrosis. Two patients with omphalocele are reported with AFP measurement. A tenfold elevation of AFP was found in the first patient. In the second case a small omphalocele associated with exstrophy of the cloaca was not accompanied by an abnormal AFP increase. The mechanism of AFP elevation is discussed.