Vertically transmitted hypoplasia of the abdominal wall musculature.

The prune belly syndrome (OMIM 100100) is an association of bladder dilation with hypoplasia of the abdominal wall muscles. This malformation sequence is due to early urethral obstruction. We report a family with abdominal wall muscular hypoplasia as an isolated defect, not associated with the urethral obstruction sequence. The proband is a q3-year-old male who presented with abdominal wall laxity and severe constipation. His mother, maternal grandmother and younger brother had varying degrees of abdominal wall muscular deficiency and constipation. His mother's condition was aggravated by her 2 pregnancies. This family shows vertical transmission (compatible with autosomal dominant or mitochondrial inheritance) of the abdominal phenotype of prune belly sequence without any evidence of urinary tract or renal pathology. The expression in the sons may remain incomplete because abdominal distention due to pregnancy will not occur.