What is Capillary Malformation/Arteriovenous Malformation Syndrome? 

Capillary malformation/arteriovenous malformation (CM-AVM) syndrome is a rare disorder of the vascular (blood vessel) system.

The syndrome is caused by a mutation in the RASA-1 gene, which functions in the development of the vascular system. The mutation can be passed down from a parent or occur by chance. It may take different forms in affected family members with some having only small vascular birthmarks and others developing significant vessel malformations.

Signs & Symptoms

Capillary malformations (CM) — characterized by flat reddish or purple patches on the face, arms and/or legs — do not usually cause health concerns. However, they can be a marker for other vascular malformations elsewhere in the body. In CM-AVM syndrome, patients may develop CMs that are atypical in color, number and location and may also form arteriovenous malformations (AVM). AVMs involve improper connections between arteries and veins and can cause serious, sometimes life-threatening health problems.


CM-AVM syndrome is a complex condition that should be assessed and diagnosed by a physician who specializes in vascular anomalies. Patients as well as family members may undergo diagnostic testing including:

  • Physical exam
  • Blood tests
  • Genetic tests
  • Magnetic resonance imaging (MRI), magnetic resonance angiography and other imaging tests


Treatment for arteriovenous malformations found in patients with CM-AVM syndrome depends on the area of the body that is involved and can include:

  • Medication to alleviate general symptoms. This can be helpful for those who are unable to have surgery.
  • Embolization: The injection of a material into the center of the lesion blocks the blood supply of the lesion.
  • Surgical removal:To increase the chance of successful surgical removal of an AVM, a pre-operative embolization may be used to reduce blood loss.

Why Choose Us?

The vascular anomalies program at Comer Children's offers an integrated and comprehensive approach to the diagnosis, care and management of vascular malformations. Our multidisciplinary team of pediatrics experts works together to educate families and to evaluate and treat children with all types of these vascular lesions.

Resources & Support for Patients with Vascular Anomalies

Patient Resources at Comer Children’s

Kids want to feel like kids, even when they're sick. Our Child Life therapists use play, art and other approaches to take some of the scare away from the hospital experience and to help kids feel as normal as possible, in spite of their disease. Located near Comer Children's, the Ronald McDonald House provides a home away from home for families while their child is hospitalized.

Patient Resources & Support Groups

These organizations and support groups may be helpful to families and patients by providing support, education and treatment information on vascular anomalies.