is a rare, progressive, blood vessel disease caused by blocked arteries at the base of the brain in an area called the basal ganglia. The name "moyamoya" means "puff of smoke" in Japanese and describes the look of the tangled vessels that form to compensate for the blockage. This condition usually affects children, but can affect adults. Affected people are at increased risk for blood clots, strokes, and transient ischemic attacks (TIAs) which are frequently accompanied by seizures and muscular weakness, or paralysis on one side of the body. Affected people may also have disturbed consciousness, speech deficits (usually aphasia), sensory and cognitive impairments, involuntary movements, and vision problems. Researchers believe that Moyamoya disease is an inherited condition because it tends to run in families.
Moyamoya syndrome is a related term that refers to cases of moyamoya disease that occur in association with other conditions or risk factors, such as neurofibromatosis, tuberculosis meningitis, sickle cell disease, leptospirosis, brain tumors, Sturge-Weber syndrome, and tuberous sclerosis. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.