U Medical School Researchers Rule Out Elastin Gene as Cause of Familial Brain Aneurysms

U Medical School Researchers Rule Out Elastin Gene as Cause of Familial Brain Aneurysms

Apr 24, 2005 6:00 PM

University of Utah researchers have ruled out mutations in the elastin gene (ELN) as the cause of familial intracranial aneurysms--a bulge in a blood vessel in the brain that runs in families and can be fatal if it bursts.

Elastin is a protein that gives elasticity to human organs and tissue and is an important component of blood vessel walls.

U of U researchers, led by Lisa Cannon-Albright, Ph.D., professor of medical informatics at the U School of Medicine, screened 16 people from 13 Utah families in which brain aneurysms occur. Each subject had been diagnosed with an aneurysm and shared a small segment of chromosome 7 previously associated with brain aneurysms.

Kang Zhang, M.D., Ph.D., assistant professor of ophthalmology and visual sciences and an investigator with the Us program in Human Molecular Biology and Genetics, screened for ELN mutations on Chromosome 7. Although Zhangs lab found variants in the gene, no ELN variants were associated with the brain aneurysms.

A familial component to brain aneurysms is well-recognized, according to Cannon-Albright. Two earlier studies, including one in 2001 at the University of Utah, showed a link between ELN mutations and brain aneurysms.

"Our (new) studies show a linkage to the region where ELN resides on the chromosome," Cannon-Albright said. "But the analysis doesnt support ELN as the gene responsible for familial brain aneurysms."

In addition to looking for genetic variations, the researchers also screened more than 500 relatives of people with brain aneurysms. Using magnetic resonance angiography, which employs radio waves to make highly detailed pictures of the brain, the researchers found more than 40 of the relatives had aneurysms, some as small as 1 millimeter, allowing those people to see a doctor for appropriate treatment.

First-degree relatives--parents, brothers and sisters, and sons and daughters--of people who have a brain aneurysm have a one-in-10 chance of also having the problem, according to Cannon-Albright.

Future research should concentrate the search for the gene(s) that cause brain aneurysms on the region of Chromosome 7 where ELN resides, according to Cannon-Albright.

"We want to find all the genes in the region and start working our way through them," she said.

Brain aneurysms occur in 3 percent to 5 percent of the population, and an estimated 2 million people in the United States currently have an unruptured aneurysm. Half of people who suffer a ruptured brain aneurysm will die within minutes and 25 percent will die of complications resulting from the aneurysm.

Other researchers on the study, all at the U of U, included Nicole Berthelemy-Okazaki, Ph.D., and Jim Farnham, both of the Department of Medical Informatics; Yu Zhao and Zhenglin Yang, both of Ophthalmology Services at the John A. Moran Eye Center; Nicola J. Camp, Ph.D., associate professor of medical informatics; Dennis Parker, Ph.D., research professor of radiology and professor of medical informatics; Jay Tsuruda, M.D., visiting scholar in medical informatics; Joel MacDonald, M.D., assistant professor of neurosurgery; Kang Zhang, M.D., Ph.D., assistant professor of ophthalmology and visual sciences.

The researchers' findings appeared online in the May edition of the journal Stroke.

# # #

Visit our News Archive for a complete list of previous News.