Somatic Mutation Links Port-Wine Birthmarks, SWS, and Melanoma of the Eye
Researchers have identified the gene mutation responsible for the rare neurological condition Sturge-Weber syndrome (SWS) and port-wine birthmarks. The scientists, from the Kennedy Krieger Institute and the Sturge-Weber Foundation, claim that this is the most significant medical advance in the pursuit of a cure for SWS.
Sturge-Weber syndrome is a rare neurological disorder characterized by a facial port-wine birthmark and neurological abnormalities, including seizures and glaucoma. Port-wine birthmarks occur in 3 in 1,000 newborns, and estimates for SWS range between one in 20,000 to 50,000 newborns. Prior to this latest research there was no known cause for the disorder, the scientists say. Treatments are available for many of the complications of the disease, but more research is needed to understand how to prevent the medical and developmental problems resulting from it.
The researchers found a mutation in the GNAQ gene on chromosome 9q21 in three individuals with SWS whose affected and unaffected tissue and blood samples underwent whole-genome sequencing. In a separate analysis, researchers detected the mutation in 23 of 26 tissue samples from patients with SWS, and in 12 of 13 samples from patients with isolated port-wine birthmarks. The mutation was not present in the control samples and in most of the unaffected samples.
The genetic mutation in the GNAQ gene is somatic, which means it occurs after conception and is not inherited or passed on to children. Notably, the GNAQ gene is the same gene that causes uveal (intraocular) melanoma, a type of melanoma that occurs in the middle layer of the wall of the eye.
The research is published online today in the New England Journal of Medicine.