Unilateral Moyamoya Phenomenon with a String-of-beads Appearance in an Elderly Patient with the c.14576G>A Heterozygous Variant of RNF213

We herein report a case of ischemic stroke in a 69-year-old man with unilateral moyamoya vessels originating from the proximal portion of the left middle cerebral artery. In addition, digital-subtraction angiography demonstrated a string-of-beads-like appearance in the cavernous portion of the left internal carotid artery. A genetic analysis revealed a heterozygous c.14576G>A variant in ring finger protein 213. The patient's younger brother had a history of hemorrhagic stroke and had been diagnosed with moyamoya disease. We finally considered that the unilateral moyamoya vessel and string-of-beads appearance observed in the current case were not simply caused by atherosclerosis, but rather represented symptoms within the moyamoya spectrum.