[Incidence and etiology of omphaloceles (author's transl)].

Omphaloceles are congenital malformations with herniation of the abdominal viscera into the umbilical cord. The incidence in newborns is 1:4300, the sex ratio 1.24:1 in favour to boys. Children with this malformation are neither more frequent at the beginning nor at the end of the sibship; the average maternal age is not increased. In about 50% other different malformations are found. All those omphaloceles, which are found as an obligatory symptom in the EMG syndrome (Wiedemann-Beckwith syndrome) to be probably in most cases autosomal recessively inherited or which are seen within a chromosomal malformation syndrome are of etiologically known origin. Omphaloceles without other malformations are mainly sporadic, less frequent in sibs, possibly due to a polygenic or multifactorial mode of inheritance. Findings in population genetics and animal experiments suggest that exogenous factors, too, can be the cause of malformation syndromes with omphaloceles.