Prune belly in trisomy 13.

Prune belly (urethral obstruction sequence) has previously been reported as an isolated malformation sequence, in association with trisomy 18 (Nevin et al., 1983) and more recently with trisomy 13 (Beckman et al., 1984). A further case associated with trisomy 13 in a fetus is reported. This emphasizes the importance of karyotyping fetuses with prune belly identified prenatally.