We have reported the case of a critically ill 17-year-old girl who had an evolving gastrointestinal infarction when she came to our institution 11 months before she died. After surgical revascularization, biopsy of the superior mesenteric artery showed FMD. We interviewed and examined all close consanguineous relatives and found abdominal bruits in the patient's younger sister and mother. Arteriograms showed total occlusion of the celiac and superior mesenteric arteries in the sister, and a subtotal celiac occlusion in the mother. Postprandial abdominal pain and constipation in the sister prompted elective mesenteric revascularization, and biopsy of the superior mesenteric artery confirmed FMD identical to that of her older sister. The mother, who is asymptomatic, has single vessel disease and has not required operative intervention. Our report strongly supports the hypothesis of a genetic basis for this arteriopathy.