RNF213 Mutation Associated with the Progression from Middle Cerebral Artery Steno-Occlusive Disease to Moyamoya Disease.

Middle cerebral artery steno-occlusive disease (MCAD) has been recognized as a different clinical entity from moyamoya disease (MMD). Although MCAD can progress to MMD, the extent to which patients actually progress and the risk factors for this progression have not been fully elucidated. We retrospectively reviewed patients with MCAD who underwent RNF213 genotyping. Demographic features, RNF213 p.R4810K mutation, medical history, and longitudinal changes in angiography were analyzed. Sixty patients with 81 affected hemispheres were enrolled. During the follow-up period, 17 patients developed MMD, and the RNF213 p.R4810K mutation was the only factor significantly associated with progression to MMD (odds ratio, 16.1; 95% CI, 2.13-731; P = 0.001). The log-rank test demonstrated that patients with the mutation had a higher risk of progression to MMD (P = 0.007), stenosis progression (P = 0.010), and symptomatic cerebral infarction or hemorrhage (P = 0.026). In Cox regression analysis the p.R4810K mutation remained a significant factor after adjusting for age group (childhood or adult onset) at diagnosis (hazard ratio, 8.42; 95% CI, 1.10-64.4). Hemisphere-based analysis also showed that the mutation was associated with a higher risk of progression to the MMD hemisphere (P = 0.002), stenosis progression (P = 0.005), and cerebral infarction or hemorrhage (P = 0.012). The RNF213 p.R4810K mutation was identified as a risk factor for progression from MCAD to MMD. Genotyping for this mutation may contribute to risk stratification in MCAD.