Duodenal atresia in dizygotic twins.

The authors report duodenal atresia occurring in both members of dizygotic twins who showed no signs of Down's syndrome, and both had normal chromosomal constitutions. They both had the two unlinked end type of atresia in the second portion of the duodenum, and direct end-to-end duodenoduodenostomy was carried out. Their postoperative courses were smooth, and both babies were discharged 32 days after birth. Their mother underwent pituitary adenoma removal and partial parathyroidectomy for multiple endocrine neoplasia (MEN-type I). She had been given hormonal supplement therapy after surgery and became pregnant after exogenous gonadotropin therapy. Environmental factors may be responsible for some cases of duodenal atresia.