SNP Shot: Genomic Insights

Capillary malformation-arteriovenous malformation syndrome (CM-AVM) affects the body's vascular system, the network of arteries, veins, and capillaries that circulate blood. Arteries transport oxygenated blood from the heart, veins return blood to the heart, and capillaries connect arteries and veins.

CM-AVM is defined by capillary malformations (CMs), which are clusters of enlarged capillaries close to the skin's surface, increasing blood flow. These CMs appear as small, circular, pink or red spots, usually on the face, arms, or legs. They may be present at birth or develop in childhood and generally don't cause health issues on their own.

While some individuals with CM-AVM only have CMs, others develop more serious vascular issues: arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs). These are irregular connections between arteries, veins, and capillaries that disrupt normal blood flow. Depending on their location, AVMs and AVFs can lead to complications such as bleeding, migraines, seizures, and heart failure. These complications can sometimes be life-threatening. In CM-AVM, AVM and AVF complications typically emerge in infancy or early childhood, although some may remain asymptomatic.

Certain vascular abnormalities found in CM-AVM resemble those in Parkes Weber syndrome. However, Parkes Weber syndrome usually also involves limb overgrowth. CM-AVM and some instances of Parkes Weber syndrome share the same genetic origin.

Inheritance:

CM-AVM follows an autosomal dominant inheritance pattern. This means that only one copy of the mutated gene in each cell is needed to cause the condition. Typically, an affected individual inherits the mutation from a parent who also has the condition. However, in some cases, the mutation is new and occurs spontaneously in individuals with no family history of CM-AVM.