Sturge-Weber syndrome (SWS) is an example of a neuro-ectodermal (neurocutaneous) disease characterized by facial port wine nevus (angiomas), on one side of the face, affecting the area innervated by the first sensory branch of the trigeminal nerve, the retina of the eye, and the ipsilateral leptomeninges. Seizures are the usual neurological manifestation in up to 80% of patients. SWS is also accompanied by the loss of nerve cells and calcification of tissue in the cerebral cortex of the brain on the same side of the body as the nevus. Convulsions usually happen on the side of the body opposite the nevus and vary in severity. Some children with SWS may have developmental delays and mental retardation. Both sexes are affected equally. Laser treatment may be used to lighten or remove the nevus and anticonvulsant medications may be used to control seizures.
SWS is caused by residual embryonal blood vessels and their secondary effects on surrounding brain tissue. A study found abnormal gene expression of fibronectin in SWS brain tissue and SWS port-wine skin fibroblasts. Another study found chromosomal abnormalities in two cultures derived from affected tissue compared to cultures from unaffected tissue of the same two individuals suggesting the presence of somatic mutation or chromosomal instability. Somatic mosaic mutation in the GNAQ gene have been identified in a few cases of SWS.