烟雾病是一种原因不明、慢性进行性的闭塞性脑血管疾病，主要表现为双侧颈内动脉末端及其大分支血管发生狭窄或闭塞，且在颅底伴有异常新生血管网。它的发病具有种族差异性和家族聚集性，可能与环境和遗传因素密切相关。相关研究表明，家族性烟雾病约占总烟雾病患病率的10%，且所占比例逐渐增加。本文报道了2例亲姐妹先后诊断为烟雾病，且临床表现均为反复的颅内出血，其中1例合并左侧脉络膜前动脉远端动脉瘤，并简要讨论了家族性烟雾病的遗传学特点。

Moyamoya disease (MMD) is an enigmatic, chronic, and progressive occlusive cerebrovascular disorder characterized by the narrowing or occlusion of the terminal segments of the bilateral internal carotid arteries and their major branches. It is also marked by an abnormal network of neovascularization at the base of the skull. The onset of the disease exhibits ethnic and familial clustering, likely due to a combination of environmental and genetic factors. Research indicates that familial MMD (F-MMD) accounts for approximately 10% of all MMD cases, with the prevalence of F-MMD gradually increasing within the spectrum of MMD. This article reports two cases of siblings successively diagnosed with MMD, both of whom exhibited recurrent intracranial hemorrhages. One case additionally involved an aneurysm at the distal portion of the left anterior choroidal artery. The paper concludes with a brief discussion of the genetic characteristics of F-MMD.