Coarctation of the aorta in dizygotic twins

The incidence of congenital heart disease is higher in monozygotic than diz ygotic twins, with a higher concordance rate. Although coarctation of the a orta has previously been reported in monozygotic twins, to the best of our knowledge it has not been described in dizygotic twins. We report here such a concurrence in dizygotic twins conceived by in-vitro fertilisation. The finding provides support for both genetic and environmental factors in the aetiology of congenital heart disease. Furthermore, it highlights our lack of data regarding the outcome of in-vitro fertilisation.