SNP Shot: Genomic Insights

Moyamoya disease is a condition affecting the brain's blood vessels, primarily the internal carotid arteries and their branches. Over time, these arteries, responsible for delivering oxygenated blood to the brain, become constricted. This narrowing reduces the amount of blood reaching the brain. To counteract this, the body creates new, smaller, and more delicate blood vessels. These clusters of tiny vessels, visible through a diagnostic angiogram, look like puffs of smoke. The disease's name, "moyamoya," comes from the Japanese expression for "something hazy like a puff of smoke."

The onset of moyamoya disease typically occurs around age 5 or between the ages of 30 and 40. Insufficient blood flow to the brain causes various symptoms, including transient ischemic attacks (TIAs or "mini-strokes"), strokes, and seizures. Furthermore, the fragile, newly formed vessels are prone to developing aneurysms (bulges) or rupturing, leading to brain hemorrhages. Individuals with moyamoya disease may also experience recurring headaches, involuntary movements (chorea), and cognitive decline. Without treatment, the symptoms of moyamoya disease tend to worsen progressively.

When the blood vessel abnormalities characteristic of moyamoya disease occur alongside other medical conditions like neurofibromatosis type 1, sickle cell disease, or Graves' disease, the condition is referred to as moyamoya syndrome.

Inheritance:

In Japan, up to 15% of individuals with moyamoya disease have a family history of the condition, suggesting a possible genetic component passed down through generations. However, the exact pattern of inheritance remains unclear. Research hints at an autosomal dominant inheritance, meaning only one copy of a mutated gene is needed to cause the disease. However, reduced penetrance is observed, meaning that some individuals carrying the mutated gene may never develop the disease.