What is Vein of Galen Malformation?

Vein of Galen malformation is a very rare condition affecting the blood vessels of the brain. The malformation develops in utero at around 6–11 weeks of embryonic development. Statistically, one case of vein of Galen malformation occurs each year in a population of about three million people. The condition affects all races and genders equally and the cause of it is unknown. The condition results in abnormal communications between the arteries and the veins in the blood vessels of the developing brain. The capillaries, which normally connect arteries to veins and function to slow blood flow allowing for the drop off of oxygen and nutrients to the brain, are missing.

Three-dimensional reconstruction of a malformation. Image courtesy of Dr Laughlin Dawes, MB, BS.

Since Vein of Galen malformations lack capillaries, the blood flow is very fast and rushes almost directly to the heart. This rush of blood can rapidly overwhelm the heart and lead to congestive heart failure. This can then affect all the other organs including the lungs, liver, kidneys and the brain. Blood drainage is towards a single deep draining vein at the base of the brain, which becomes markedly enlarged. The high flow of blood can also interfere with the normal blood drainage of the brain potentially causing hydrocephalus (water on the brain).

Other names for this condition include:

Arteriovenous Malformation (AVM)
Vein of Galen Aneurysmal Malformation
Vein of Galen Aneurysm
Galenic Arteriovenous Malformation

More Information

• Signs, Symptoms and Diagnosis of Vein of Galen Malformation
• Treatment of Vein of Galen Malformation
• When Should the Malformation be Treated?
• Life After Treatment