Clinical Presentation and Stroke Incidence Differ by Moyamoya Etiology.

In this single-center cohort, moyamoya subgroups differed with respect to clinical and radiographic characteristics, with neurofibromatosis-associated moyamoya syndrome having a milder phenotype and Down syndrome-associated moyamoya portending a more aggressive course. These findings need confirmation in a larger, multi-center cohort with longer duration of follow-up.