Familial association of basilar bifurcation aneurysm and moyamoya disease--four case reports.

Four patients presented with familial intracranial aneurysms and familial moyamoya disease, including one patient with both familial intracranial aneurysm and moyamoya disease. Basilar bifurcation aneurysms were present in two patients, moyamoya disease in one, and both basilar bifurcation aneurysm and moyamoya disease in one. These events are most likely to arise from different genetic abnormalities associated with basilar bifurcation aneurysm and moyamoya disease.