The researchers report that people with key variations in a gene that affects the ability of blood vessels to relax are 10 times more likely to suffer a stroke from a ruptured brain aneurysm than people who have aneurysms but lack these key genetic variations.

"There has been a search for a marker that would identify patients with rupture-prone aneurysms for a very long time because this disease can strike like lightning”, says G. Vini Khurana, M.D., Ph.D., at Mayo Clinic.

The Mayo Clinic researchers have found the first genetic marker to help identify which cases of a condition known as sporadic brain aneurysm are at highest risk for death and disability due to rupturing and subsequent bleeding into the brain. While development of sporadic brain aneurysm is relatively common many people have them and have no symptoms or warning signs that they could be at risk of catastrophic rupture that is imminently life endangering.

The researchers are the first to identify specific genetic variations or polymorphisms associated with an approximately 10-fold increased risk of a ruptured aneurysm. The experimental blood test researchers developed detects specific variations in the gene that encodes an important blood vessel-relaxation protein.

To determine the role of nitric oxide synthesis gene variations in ruptured brain aneurysms, the Mayo Clinic team screened the genetic variants of 49 patients who had unruptured brain aneurysms, and compared them with the genetic variants of 58 emergency room patients with ruptured aneurysms.

Blood samples were taken from all, and DNA analysis performed. The genetic differences were striking. "Our findings are the first to present strong evidence that the reason for sporadic brain aneurysm rupture may be genetic” says Dr. Khurana,; Source: Mayo Clinic