The most common cause of arteriovenous malformation (AVM) is unknown. However, some studies suggest that genetic factors may play a role in the development of AVMs. For example, a meta-analysis of 346 cases found that mutations in the genes associated with the two main pathways of angiogenesis (the formation of new blood vessels) were present in 8.5% of the cases. Other studies have identified an association between AVMs and mutations in genes responsible for cell adhesion and those involved in the regulation of cell proliferation.
It is also believed that environmental factors, such as exposure to certain chemicals, radiation, or viruses, may contribute to the development of AVMs. A recent study of 136 patients with AVM found that those exposed to radiation had a higher risk for developing an AVM compared to those without radiation exposure.
In addition to genetic and environmental factors, AVMs may also be caused by trauma or a vascular abnormality present at birth. Trauma to the head, neck, or spinal cord can cause a disruption in the normal flow of blood and may lead to the formation of an AVM. Vascular abnormalities present at birth, such as a narrowing of the arteries, can also lead to the formation of AVMs.
Finally, AVMs can also be caused by tumors, which can disrupt the normal flow of blood and cause the formation of an AVM.