Moyamoya disease presenting with transient nonfocal neurological attacks in an Indian woman carrying a previously unreported RNF213 missense variant (p.Thr554Ile)

Moyamoya disease is a rare cerebrovascular disorder characterized by progressive internal carotid artery stenosis and compensatory collateral vessel formation, producing a characteristic "puff of smoke" angiographic appearance. Genetic predisposition, particularly involving the RNF213 gene, plays a central role. We report a 48-year-old Indian woman with type 2 diabetes, arterial hypertension, and a prior transient ischemic attack who presented with intermittent bilateral upper limb paresthesia. Imaging revealed bilateral supraclinoid internal carotid artery stenosis (Suzuki stage III). Genetic testing identified a heterozygous RNF213 missense variant (Thr554Ile, rs766831703), which is extremely rare in global databases and predicted to be deleterious by multiple in silico tools. This variant has not been previously described in association with Moyamoya disease. The patient underwent bilateral superficial temporal artery to middle cerebral artery bypass, achieving sustained clinical improvement without recurrent events over two years.