Sturge-Weber syndrome classically consists of a facial capillary malformation (previously called port-wine stain or port-wine birthmark), eye abnormalities and brain involvement. These all result from a change early in development affecting the formation of blood vessels in a similar area, and occur on the same side of the body. Abnormal blood vessels around the eye can lead to poor drainage of blood from the eye, resulting in increased pressure in the eye (called “glaucoma”). Abnormal blood flow in the brain and the meninges (outer lining of the brain) can lead to seizures and developmental delays.

Recently a genetic change has been identified in Sturge-Weber syndrome. It is found in the affected tissues (skin and brain) but not in the normal tissue nearby. The same mutation has also been found in capillary malformations that are not associated with the syndrome, so genetic testing cannot be used to diagnose Sturge-Weber.