MedGen

Capillary malformation-arteriovenous malformation (CM-AVM) syndrome is characterized by the presence of multiple small (1-2 cm in diameter) capillary malformations mostly localized on the face and limbs. Some affected individuals also have associated arteriovenous malformations (AVMs) and/or arteriovenous fistulas (AFVs), fast-flow vascular anomalies that typically arise in the skin, muscle, bone, spine, and brain; life-threatening complications of these lesions can include bleeding, congestive heart failure, and/or neurologic consequences. Symptoms from intracranial AVMs/AVFs appear to occur early in life. Several individuals have Parkes Weber syndrome (multiple micro-AVFs associated with a cutaneous capillary stain and excessive soft-tissue and skeletal growth of an affected limb). [from GeneReviews]

Vein of Galen aneurysmal malformation is a choroidal type of arteriovenous malformation that develops between 6 and 11 weeks of gestation. It results from 1 or more arteriovenous fistulas shunting blood toward the prosencephalic vein of Markowski, the embryonic precursor of the vein of Galen. This abnormal shunt leads to progressive dilation of the vein and prevents its involution and subsequent development into the vein of Galen. [from HPO]