Moyamoya disease (MMD) is the most common pediatric cerebrovascular disease in Eastern Asian countries but the etiology is not well understood. Circular RNAs (circRNAs) have been implicated in various biological processes, but their role in the development of MMD remains unclear. To address this issue, we carried out a comparative circRNA microarray analysis of blood samples obtained from patients with MMD and healthy subjects and identified 146 circRNAs that were differentially expressed between the two groups. Of these, 29 were upregulated and 117 were downregulated in patients as compared to controls (fold change 2.0 and P < 0.05). The microarray results were validated by quantitative reverse-transcription PCR. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses revealed that the differentially expressed circRNAs were primarily involved in angiogenesis, metabolism, and immune responses in MMD. In addition, the mitogen-activated protein kinase signaling pathway was found to be the core regulatory pathway associated with disease pathogenesis. These results indicate that specific circRNAs are aberrantly expressed in MMD and are potential therapeutic targets for its treatment. (C) 2017 Published by Elsevier B.V.