Family-Based Moyamoya Susceptibility and Early Detection

Inclusion Criteria: * Participants must belong to 1 of the following 3 cohorts: Moyamoya disease cohort: diagnosed with primary moyamoya disease according to standard diagnostic criteria, with progressive stenosis or occlusion at the terminal internal carotid arteries and/or their major branches and typical collateral vessels on DSA, CTA, or MRA; newly diagnosed and previously diagnosed cases are both eligible; no age or sex restriction. First-degree relative cohort: first-degree blood relatives of patients with moyamoya disease, including parents, children, and siblings; no age or sex restriction; no clinical diagnosis of moyamoya disease and no history of stroke or other cerebrovascular events at enrollment; baseline MRI does not show definite moyamoya disease, although mild changes are allowed. Healthy control cohort: no family history of moyamoya disease; no personal history of cerebrovascular disease; no major abnormalities on physical examination or baseline screening; age and sex distribution matched as closely as possible to the moyamoya disease cohort. Exclusion Criteria: * Major systemic or central nervous system diseases that may interfere with study results or substantially affect survival or adherence, such as advanced malignant tumors, active tuberculosis or other serious infections, active systemic lupus erythematosus, or severe hepatic or renal dysfunction. Atypical cerebrovascular lesions on baseline imaging, such as widespread atherosclerotic stenosis or congenital vascular malformations. Inability to complete examinations or follow-up, including MRI contraindications such as non-compatible metal implants or severe claustrophobia, expected difficulty completing follow-up because of long-term relocation, poor communication access, poor adherence, or other situations judged by the investigators to make participation inappropriate. Pregnant women.