Sturge-Weber syndrome

Sturge-Weber syndrome is a rare congenital disorder that affects the skin, the central nervous system, and the eyes together, and it arises from a somatic mutation in the GNAQ gene occurring after conception rather than from an inherited genetic trait. The mutation disrupts the normal development of small blood vessels, leaving in place a network of vessels that should have regressed before birth; the result is a leptomeningeal angioma, an abnormal tangle of blood vessels over the surface of the brain, which reduces oxygen and blood flow to the underlying brain tissue. The condition is best known for producing a port-wine stain birthmark on the face, typically on the forehead or upper eyelid, and it can also cause seizures, developmental delay or intellectual disability, and glaucoma or other eye complications from increased pressure inside the eye. Physicians recognize three types: type 1, the most common, combining a facial birthmark with the brain angioma and often glaucoma; type 2, a facial birthmark alone with a possibility of glaucoma but no brain involvement; and type 3, an angioma confined to the brain with no visible facial mark. The syndrome takes its name from the English physician William Allen Sturge, who first described it in 1879, and from Frederick Parkes Weber, who added further clinical detail in 1922. It is estimated to affect about one in fifty thousand newborns.