NF1 and Moyamoya disease: Conversely, even though neurofibromin is known to be expressed in vascular smooth muscle cells, little is known about its function relating to controlling endothelial cell proliferation.8 Interestingly, despite the proximity of the NF-1 gene (17q11.2) to the gene for familial moyamoya disease (17q25), NF-1 does not participate in occurrences of moyamoya disease.9