Port-Wine Stain Birthmark And Sturge-Weber Syndrome Tied By Gene
May 12, 2013

Genetic Mutation Responsible For Port-Wine Stain Birthmark Identified

redOrbit Staff & Wire Reports — Your Universe Online

Researchers from the Kennedy Krieger Institute in Maryland have discovered a genetic mutation they say is responsible for both port-wine stain birthmarks and a rare neurological condition known as Sturge-Weber Syndrome (SWS).

According to The Telegraph, the birthmarks are caused by “abnormally dilated capillaries in the skin, which produce reddish to purplish discoloration.” Now the researchers have discovered the condition is result of a mutation that occurs prior to birth — a mutation also responsible for SWS, a syndrome which has been linked to the birthmarks, as well as glaucoma, seizures and physical weakness.

Currently, both conditions can only be treated by using prescription drugs, surgery, or lasers, and even then the success rate is “limited,” the UK newspaper said. Now, however, the Kennedy Krieger Institute researchers have discovered an underlying genetic cause that they hope will lead to the development of drugs capable of blocking activity in the mutant gene and providing a more effective treatment option for patients.

“This is a complete game changer for those with Sturge-Weber syndrome and the millions born with port-wine birthmarks,” Dr. Anne Comi, Director of the Institute's Hunter Nelson Sturge-Weber Center and co-senior author of the study, said in a statement. “Now that we know the underlying genetic mutation responsible for both conditions, we're hopeful that we can move quickly towards targeted therapies, offering families the promise of new treatments for the first time.”

“The discovery marks a milestone for the field of genetics, where advances have only recently made it possible to find these rare ℠lightning strike´ mutations,” added HealthDay Reporter Brenda Goodman. “It is also a triumph for parents of children with the rare disorder who began saving samples of skin and brain tissue years ago, before the technology was even in place to test them.”

The somatic mutation (a genetic change which occurs after conception and only affects part of the body) was discovered in the laboratory of Dr. Jonathan Pevsner, Director of Bioinformatics at the Kennedy Krieger Institute. He and his colleagues performed whole genome sequencing on both affected and unaffected tissue and blood samples from three subjects suffering from SWS. All three samples shared one common somatic mutation originating on chromosome 9q21.

“In a separate analysis, the researchers confirmed the finding by detecting the mutation in 23 out of 26 tissue samples from subjects with SWS and 12 out of 13 samples from subjects with isolated port-wine birthmarks,” the Institute explained. “The control samples, and most of the unaffected samples, did not possess the mutation. These analyses also revealed the surprising outcome that the gene involved in SWS is the same gene implicated in uveal melanoma, a type of melanoma that occurs in the eye.

“With the discovery of the gene and pathway involved in SWS and port-wine stains, researchers can now begin investigating drugs that selectively inhibit the implicated pathways. The link to melanoma may also influence research and lead to new directions for the treatment of both conditions in the future,” they added. “In revealing that SWS is caused by a somatic mutation, researchers have also confirmed for the first time that Sturge-Weber is not an inherited syndrome — a meaningful insight for many parents.”