Familial cerebral aneurysms. A bias for women.

BACKGROUND AND PURPOSE

We evaluated the influence of gender on the formation and rupture of familial cerebral aneurysms.

METHODS

We studied 30 patients with ruptured cerebral aneurysms from 14 consecutive families. These patients were compared with the patients with sporadic aneurysms reported by the first Cooperative Study.

RESULTS

Eighty percent of familial aneurysms occurred in women versus 59% of sporadic aneurysms (P < .05, chi 2 test). This overrepresentation of women occurred at below the age of 50 years, where 78% of patients with familial aneurysms were women compared with 45% for sporadic aneurysms (P < .01, chi 2 test). Above this age, there was no statistical difference in incidence of familial aneurysms in men or women compared with sporadic aneurysms. In women with familial aneurysms, rupture occurred before the age of 50 years in 59%, compared with 31% for sporadic aneurysms (P < .01, chi 2 test). In four of five families, aneurysms ruptured within 10 years of each other in sisters (mean, 6 years). Multiple aneurysms were equal in both groups (17%), but multiple familial aneurysms occurred mainly in women. There was no difference in the site of single cerebral aneurysms in either group, but familial aneurysms in females occurred at the same site in five of eight families (62%) and in 11 of 17 mother-daughter or sister pairs (65%), compared with 20% for two randomly selected sporadic aneurysms (P < .01).

CONCLUSIONS

There is an overrepresentation of women with ruptured familial aneurysms compared with those with sporadic aneurysms. Familial aneurysms rupture in females predominantly before the age of 50, in the same decade, and at the same site within families in the majority of cases. These observations support a possible genetic cause for cerebral aneurysms and a possible hormonal contribution to their rupture.