Sturge-Weber syndrome is a rare congenital (present at birth) condition that has an identified genetic mutation, although the same mutation is found in capillary malformations that are not associated with Sturge-Weber syndrome.

A port-wine stain (capillary malformation) on the face and often the eyelids may signal the presence of this syndrome; however, not all infants with a facial capillary malformation have this syndrome. Variation in the size of the facial lesion is common, and one or both sides of the face may be involved.

The mucous membranes (lining of the eyes, mouth and nose) and the meninges (covering of the brain) also can be affected.