Yes and no
In moyamoya, the inner layer (intima) of the internal carotid artery (ica) overgrows causing blockage of the lumen (opening) of the artery.
The icas are two of the 4 major arteries supplying all of the brain. Collaterals form & look like smoke (moyamoya in japanese) on x-ray. Moyamoya can be congenital or acquired. There is also a possible hereditary component on chromosome 17.