Moyamoya Disease – Causes and Symptoms of Moyamoya Disease

Recognised in Japan in the 1960s, this is athe syndrome is a consequence or result of
progressive occlusive cerebral arteritis affectinganother underlying disorder. In secondary
the distal internal carotid arteries near the Circle ofMoyamoya syndrome, when it is not a result of a
Willis. Moyamoya is Japanese for "puff of smoke"genetic cause, it is important for the physician to
and describes the appearance of the resultantdetermine the root underlying cause.
network of abnormal small collateral vessels seenSymptoms of Moyamoya Disease
on angiography. There is a familial form which linksThe initial symptoms of moyamoya disease are
to a gene on chromosome 17q25 - though thesomewhat different in children and adults. In
exact underlying cause remains unknown.children, there is ischemia due to stenosis and
Moyamoya Disease is a rare disorder of uncertainocclusion of the circle of Willis, a ring of arteries at
cause that leads to irreversible blockage of thethe base of the brain.
main blood vessels to the brain as they enter intoChildren also often experience temporary
the skull. This blockage tends to cause strokes orweakness in one or more of their extremities
seizures. The process of blockage (vascularduring strenuous physical activity or when crying.
occlusion) once it begins tends to continue despiteAdults can also present with brain hemorrhage
any known medical management unless treatedcausing neurologic symptoms in addition to
with surgery.nonhemorrhagic strokes, TIA’s and
Causes of Moyamoya Diseaseheadaches.
The cause of moyamoya disease is not known.The symptoms and clinical course vary widely and
However, researchers suspect there may be adepend upon the location and severity of the
genetic link because of its high rate of incidence inhemorrhage or damage. Thus signs and
certain Japanese families.symptoms may range from asymptomatic to
Researchers suspect a genetic link because of thetransient events to severe neurologic deficits.
9 percent incidence of the disease found in certainIntracranial hemorrhage is the most common
Japanese families. A gene for familial moyamoyasymptom. Ischemic symptoms such as those
disease has been located on chromosome 17q25found in children may also occur.
and further study of the gene may reveal theIn children, the first symptom of Moyamoya
cause of the disorder.disease is often stroke, or recurrent transient
The cause of moyamoya disease is unknown.ischemic attacks (TIA, commonly referred to as
Possible explanations for the disorder include“mini-strokes”), frequently accompanied
injuries to the brain, infection, multifactorialby muscular weakness or paralysis affecting one
inheritance, genetic factors, or other causes. Forside of the body, or seizures.
example, moyamoya disease has been associatedOther signs and symptoms that occur in both
with meningitis, radiation therapy to the skull inchildren and adults include headaches, altered
children, and genetic conditions such as Downconsciousness, speech difficulties, vision problems,
syndrome, neurofibromatosis, and sickle cellinvoluntary movements, mental retardation,
anemia.psychiatric problems and difficulty with sensory
Approximately 10% of cases of Moyamoyaand cognitive functions. Paralysis can also occur in
syndrome are due to a genetic cause and arethe feet, legs or upper extremities. Most suffer
termed primary Moyamoya syndrome. Secondaryfrom progressive cognitive deterioration and will
Moyamoya syndrome refers to cases in whicheventually die due to intracerebral hemorrhage.