Moyamoya Disease in North America

Abstract

Moyamoya disease (MMD) was first described in the Japanese medical literature in 1957 by Takeuchi and Shimizu [1]. The term “moyamoya” (Japanese for “puff of smoke”), was coined by Suzuki and Takaku in 1969 to describe the diagnostic appearance of angiogenesis on catheter angiogram [2]. Since its initial discovery, the features of the disease have become clearer; however, its etiology remains unknown. MMD is a chronic cerebrovascular disease characterized by stenosis or occlusion of the bilateral terminal internal carotid arteries resulting in the characteristic development of an abnormal vascular network in the areas of the arterial occlusions [3]. It is hypothesized that, in the setting of arterial stenosis or occlusion, hypoxic regions of the brain induce deep collateral flow through dilated and tortuous perforating arteries. It has been shown that this native revascularization strategy is orchestrated by the expression of various angiogenic signaling cascades [4, 5]. Despite intense research, the etiology of MMD remains unclear [6]. Familial MMD has been noted in as many as 15% of patients, indicating an autosomal dominant inheritance pattern with incomplete penetrance. Genetic analyses in familial MMD and genome-wide association studies represent promising strategies for elucidating the pathophysiology of this condition. A recent study described that carriers of a mutation in the vascular smooth muscle cell-specific isoform of alpha-actin can present with a diversity of vascular diseases, including premature onset of coronary artery disease and thoracic artery aneurysm and dissection, as well as MMD [7].