Long-term outcomes in the pre-moyamoya stage of <i>RNF213</i>-related vasculopathy presenting with ischaemic stroke or transient ischaemic attack: insights from the NCVC Genome Registry.

Background: -related vasculopathy remain poorly characterised in longitudinal studies. Methods: This multicentre, prospective, longitudinal study was conducted from March 2017 to March 2022. It included patients with ischaemic stroke (IS) or transient ischaemic attack (TIA) within one week of onset. Patients with moyamoya disease were excluded. The primary outcome was recurrent symptomatic IS or TIA. Subgroup analyses with Essen Stroke Risk Score (ESRS) assessed whether the variant improved risk stratification beyond traditional factors. A retrospective validation cohort was used for sensitivity analysis. Findings: A total of 1267 patients were prospectively enrolled from eight comprehensive stroke centres across Japan. Among these patients (469 [37.0%] women; median age 75 years), 36 (2.8%) carried the variant. The median follow-up period was 3.61 years. The variant was an independent predictor of the primary outcome (adjusted hazard ratio [aHR] 5.58, 95% confidence interval [CI] 2.15-14.54). Even variant carriers with low ESRS had a higher risk of the primary outcome (aHR 4.26, 95% CI 1.32-13.71) than non-carriers with high ESRS. Among patients with largr-artery atherosclerosis, the variant remained significantly associated with the primary outcome (aHR 4.90, 95% CI 1.32-18.25). Among the variant carriers, 2.8% were newly diagnosed with moyamoya disease. In the validation cohort of the National Cerebral and Cardiovascular Center (n = 716), the variant remained an independent predictor of the primary outcome (aHR 4.47, 95% CI 2.33-8.58). Interpretation: p.R4810K variant increases the risk of recurrent ischaemic events and identifies a distinct patient group with IS or TIA at "pre-moyamoya" stage. Funding: The Japan Agency for Medical Research and Development (JP21ek0210120 and JP21ek0210126).