De Novo Development of Moyamoya Disease in an Adult Female with a Genetic Variant of the RNF-213 Gene: Case Report

Background The de novo development of moyamoya disease (MMD) in adults is extremely rare, with only 2 cases being previously reported. Furthermore, the mechanisms underlying the progression of adult MMD have not been elucidated yet. Case report A transient ischemic attack occurred in a 46-year-old woman, owing to progressive MMD. Magnetic resonance (MR) angiography performed 7 years before the diagnosis of MMD did not detect any steno-occlusive changes in the major intracranial vessels, including the internal carotid artery (ICA) and the middle cerebral artery (MCA). However, during the last 2 years, serial MR angiography revealed the gradual progression of left MCA stenosis and ultimately showed apparent stenosis of the bilateral terminal ICA to proximal MCA. Catheter angiography confirmed the definitive diagnosis of MMD. A genetic analysis of RING-finger protein (RNF)-213, an MMD susceptibility gene, revealed that not only the patient, but also her sister, brother, and daughter had the heterozygous variant of the RNF-213 gene. Because of hemodynamic compromise with ischemic symptoms, the patient underwent revascularization surgery on the affected hemisphere, without complications. She had no cerebrovascular event in the postoperative follow-up period of 8 months, and there was no evidence of the further progression of MMD. Conclusion We herein present the entire clinical course of the de novo development of MMD in a female adult. Newly developed MMD in an adult patient with a characteristic variant of the RNF-213 gene appears to be unique.