Question: What is (are) Moyamoya disease ?
Answer: Moyamoya disease 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: GARD

Question: What are the symptoms of Moyamoya disease ?
Answer: What are the signs and symptoms of Moyamoya disease? The Human Phenotype Ontology provides the following list of signs and symptoms for Moyamoya disease. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Abnormality of the cerebral vasculature 50% Cognitive impairment 50% Seizures 50% Ventriculomegaly 50% Autosomal recessive inheritance - Inflammatory arteriopathy - Telangiectasia - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD

Question: What causes Moyamoya disease ?
Answer: What causes Moyamoya disease? In some families, risk for moyamoya disease is inherited. Changes in the RNF213 gene have been associated with the condition. There are other gene changes involved in moyamoya disease, that remain to be found. Factors such as infection or inflammation, likely also play a role in the condition's development in these families. Other people develop moyamoya syndrome or phenomenon. Moyamoya syndrome can occur in association with many different conditions, such as with infections, atherosclerosis (clogged arteries), blood disorders (for example sickle cell disease or beta thalassemia), vasculitis, autoimmune conditions (for example Lupus, thyroid disorders, Sneddon syndrome), connective tissue disorders (for example neurofibromatosis (NF) type 1 or Tuberous sclerosis), chromosome disorders, metabolic diseases, head trauma or radiation, brain tumors, and heart disease, to name a few.
Source: GARD