Sturge–Weber syndrome, sometimes referred to as encephalotrigeminal angiomatosis, is a rare congenital neurological and skin disorder. It is one of the phakomatoses and is often associated with port-wine stains of the face, glaucoma,seizures, mental retardation, and ipsilateral leptomeningeal angioma. It is characterized by abnormal blood vessels on the brain surface. Normally, only one side of the brain is affected.

Sturge-Weber is an embryonal developmental anomaly resulting from errors in mesodermal and ectodermal development. Unlike other neurocutaneous disorders (phakomatoses), Sturge-Weber occurs sporadically (i.e., does not have a hereditary etiology). It is caused by a somatic activating mutation occurring in the GNAQ gene.

Symptoms
Sturge–Weber syndrome is usually manifested at birth by a port-wine stain on the forehead and upper eyelid of one side of the face. The birthmark can vary in color from light pink to deep purple and is caused by an overabundance of capillariesaround the ophthalmic branch of the trigeminal nerve, just under the surface of the face. There is also malformation of blood vessels in the pia mater overlying the brain on the same side of the head as the birthmark. This causes calcification of tissue and loss of nerve cells in the cerebral cortex. Neurological symptoms include seizures that begin in infancy and may worsen with age. Convulsions usually happen on the side of the body opposite the birthmark and vary in severity. There may also be muscle weakness on the side of the body opposite the birthmark. Some children will have developmental delays and mental retardation; about 50% will have glaucoma (optic neuropathy often associated with increased intraocular pressure), which can be present at birth or develop later. Increased pressure within the eye can cause the eyeball to enlarge and bulge out of its socket (buphthalmos). Sturge–Weber syndrome rarely affects other body organs.

Treatment
Treatment for Sturge–Weber syndrome is symptomatic. Laser treatment may be used to lighten or remove the birthmark. Anticonvulsant medications may be used to control seizures. Doctors recommend early monitoring for glaucoma, and surgery may be performed on more serious cases. When one side of the brain is affected and anticonvulsants prove ineffective, the standard treatment is neurosurgery to remove or disconnect the affected part of the brain (hemispherectomy). Physical therapy should be considered for infants and children with muscle weakness. Educational therapy is often prescribed for those with mental retardation or developmental delays, but there is no complete treatment for the delays. Brain surgery involving removing the portion of the brain that is affected by the disorder can be successful in controlling the seizures so that the patient has only a few seizures that are much less intense than pre-surgery. Surgeons may also opt to "switch-off" the affected side of the brain.

Latanoprost (Xalatan), a prostaglandin, may significantly reduce IOP (intraocular pressure) in patients with glaucoma associated with Sturge–Weber syndrome. Latanoprost is commercially formulated as an aqueous solution in a concentration of 0.005% preserved with 0.02% benzalkonium chloride (BAC). The recommended dosage of latanoprost is one drop daily in the evening, which permits better diurnal IOP control than does morning instillation. Its effect is independent of race, gender or age, and it has few to no side effects. Contraindications include a history of CME, epiretinal membrane formation, vitreous loss during cataract surgery, history of macular edema associated with branch retinal vein occlusion, history of anterior uveitis, and diabetes mellitus. It is also wise to advise patients that unilateral treatment can result in heterochromia orhypertrichosis that may become cosmetically objectionable.