Request an Appointment Online, or call us at (888) 824-0200

The University of Chicago Medicine - Comer Children's Hospital

Types of Vascular Anomalies: Capillary Malformation/Arteriovenous Malformation (CM-AVM) Syndrome (RASA-1)

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

The CM-AVM syndrome was first described in 2003. The syndrome is caused by a mutation in the RASA-1 gene, which functions in development of the vascular system. The mutation can be passed down from a parent or occur by chance (sporadically). It may take different forms in affected family members, with some having only small vascular birthmarks and some developing significant vessel malformations.

Signs and 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 to block the blood supply of the lesion.
  • Surgical removal, in some cases. To increase the chance of successful surgical removal of an AVM, a pre-operative embolization may be used to reduce blood loss.

About Our Program

The Vascular Anomalies Program at the University of Chicago Medicine Comer Children’s Hospital offers an integrated and comprehensive approach to the diagnosis, care and management of hemangiomas and 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. » Read more about our program and our team.