Bilateral fibromuscular dysplasia in identical twins.

Fibromuscular dysplasia is an arterial occlusive disorder that often affects the renal arteries and leads to renovascular hypertension. The cause of this disease is unknown. However, the occurrence in siblings suggests that genetic factors may play a role. We describe two cases involving hypertensive identical twins with fibromuscular dysplasia of the renal arteries. This unique clinical case reinforces a possible hereditary nature of this arterial occlusive disorder.