もやもや病は，内頚動脈終末部の進行性狭窄と脳底部を中心とする異常血管網の発達を特徴とする原因不明の希少疾患である．2011年にわが国で感受性遺伝子RNF213 が同定され，その臨床的意義や生理的機能の解明に向けた研究が続けられている．ただし，RNF213 変異単独では，本疾患の発症に関してすべてを説明することはできていない．そのため，その他の因子の関与が強く想定され，エピジェネティクスの観点からも病態研究が始められつつある．本稿では，もやもや病の疫学的，病理学的背景のほか，もやもや病遺伝研究の歴史的変遷と最新の知見について述べる．

We evaluated predictive factors for prolonged hypotension after carotid artery stenting by retrospectively analyzing 88 lesions of 77 consecutive patients (mean age: 69.9±8.0 years). Easy Wall stent was applied in 14 lesions, SMART stent in 35, Protege stent in 15, Aurora stent in 11 and Precise stent in 13. We investigated correlations between the incidence of prolonged (≧3 hours) hypotension below 90 mmHg and clinical characteristics, angiographic findings and kind of deployed stents. Postprocedural hypotension occurred in 44 lesions (50%), and medical treatment (intravenous administration of catecholamines) was required in 21 lesions (23.9%). Although there was no permanent neurological deficits related with postprocedural hypotension, transient neurological deficits including consciousness disturbance were found in 5 patients. Predictive factors of prolonged hypotension were assessed by univariate and multivariate analyses. Among angiographic characteristics, calcifications at the carotid bifurcation (present vs. absent: p=0.004) were statistically significant on multivariate analysis. Although other variables including age, gender, side of lesion and degree of stenosis were not associated with postprocedural hypotension after carotid stenting, SMART (eR) stent and Protege stent were accompanied with frequent occurrence of prolonged hypotension in this study. Among angiographic variables, the presence of calcification at the carotid bifurcation can be used to identify patients at risk for postprocedural hypotension after carotid stenting. Furthermore, such identification may help us prevent a perioperative complication of CAS for high-risk patients.