FIBROMUSCULAR DYSPLASIA OF THE INTERNAL CAROTID-ARTERY ASSOCIATED WITH ALPHA(1)-ANTITRYPSIN DEFICIENCY

OBJECTIVE: A deficiency of alpha(1)-antitrypsin has been implicated in the development of various disorders affecting medium-sized arteries, including intracranial aneurysms, cervicocephalic arterial dissection s, and fibromuscular dysplasia (FMD). We performed alpha(1)-antitrypsi n phenotyping in three consecutive patients who underwent bypass surge ry for FMD of the extracranial internal carotid artery to test the hyp othesis that alpha(1)-antitrypsin deficiency is a genetic risk factor for the development of FMD. METHODS: The study population consisted of three women (aged 37, 49, and 53 years, respectively) who had bilater al internal carotid artery stenosis caused by FMD. The indications for surgery included ocular or cerebral ischemic symptoms in two patients and progressive stenosis in one patient. The diagnosis of FMD was con firmed by histological examination of the resected segment of artery. The alpha(1)-antitrypsin phenotype was determined by isoelectric focus ing in polyacrylamide gels. RESULTS: Two of the three patients had a h eterozygous alpha(1)-antitrypsin deficiency (PiMZ phenotype). Patholog ical examination of the resected arterial segment showed typical media l FMD with focal intimal fibroplasia in both patients with the PiMZ ph enotype. CONCLUSION: These findings suggest that a heterozygous alpha( 1)-antitrypsin deficiency may be a genetic risk factor for the develop ment of FMD of the internal carotid artery.