Definition

A rare genetic condition that causes abnormalities of blood vessels, including swelling of the capillaries (small blood vessels) near the surface of the skin. The swollen capillaries usually appear as small, round, pink or red spots on the skin of the face, arms, and legs. They may appear at birth or develop during childhood. More serious blood vessel abnormalities that affect the skin, muscle, bone, spine, brain, and heart may also occur. These can lead to serious problems, including abnormal bleeding, migraines, seizures, and congestive heart failure. Capillary malformation-arteriovenous malformation syndrome is a type of disease called a RASopathy that is caused by mutations (changes) in the RASA1 gene. This gene makes a protein involved in a cell signaling pathway that controls many important cell functions. Also called CM-AVM syndrome.