Sturge-Weber syndrome (SWS) is a neurological disorder marked by a distinctive port-wine stain on the forehead, scalp, or around the eye. This stain is a birthmark caused by an overabundance of capillaries near the surface of the skin. Blood vessels on the same side of the brain as the stain may also be affected. A large number of people with SWS experience seizures or convulsions. Other complications may include increased pressure in the eye, developmental delays, and weakness on one side of the body.