Adult unilateral moyamoya disease with familial occurrence in two definite cases: a case report and review of the literature.

We documented an interesting case of adult "unilateral (probable)" moyamoya disease displaying familial occurrence in two "definite" cases. A 55-year-old female presented with motor aphasia, involuntary movement of the right hand and right homonymous hemianopia due to cerebral infarction. Cerebral angiography revealed typical angiographic findings on the left side and normal findings on the right side; consequently, the patient was diagnosed with probable moyamoya disease. Previously, her mother and nephew had been diagnosed with definite moyamoya disease with bilateral involvement. The patient continued to exhibit unilateral involvement on angiography for more than 4 years. Clinical features such as absence of familial occurrence suggest that most cases of probable moyamoya disease are distinct from definite cases, especially in adults. To the best of our knowledge, this report appears to be the first involving an adult probable case characterized by familial occurrence. The literature pertaining to adult probable moyamoya disease was reviewed and the etiology of this disease was discussed.