Umbilical cord agenesis in limb body wall defect.

The term "Limb Body Wall Defect" (LBWD) refers to a variable group of congenital defects having in common abdomino- or thoraco-schisis and limb deficiency. Three general pathogenic mechanisms have been proposed for this disorder: amnion rupture, vascular disruption, and embryonic malformation. We hypothesize that there are subsets of "Limb Body Wall Defect," which have similar structural abnormalities and a common pathogenesis. We report on five cases of LBWD that were selected by using more restrictive criteria. An infant or fetus was included if it had abdominoschisis with a broad attachment of skin to amnion at the site of the abdominal wall defect, limb defects, and umbilical cord agenesis. Autopsy detected additional common structural defects. All had evisceration of the gastrointestinal structures into the extra-embryonic coelomic space with structural abnormalities of the intestines. All had scoliosis, thoracic deformities, pulmonary hypoplasia, and structural abnormalities of the cloaca and urogenital ridge. Four of five had meningomyelocele. Three had exstrophy of the cloaca. The four females all had ovarian agenesis and incomplete Mullerian fusion. None had normal development of the external genitalia. We propose that the pathogenesis was a primary malformation of body wall closure, with abnormal fusion of the amnion, which had occurred in the first month of development.