"Arteriovenous malformations (AVMs) are abnormal tangles of arteries and veins that belong to a group of disorders known as vascular malformations. Although not completely understood, they typically develop in the womb or soon after birth and may be linked to genetic mutations. When AVMs are located in the brain or spinal cord, they're called neurological AVMs.
Although people are born with AVMs, symptoms may not develop until adulthood, often between 20 to 40 years of age, after the condition progresses, and in most adults, they cause no health problems. About 1 percent of those affected, however, experience life-threatening complications."


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