Originally Published MDDI May 2005

R&D DIGEST

Maria Fontanazza

Identifying sporadic brain aneurysms with a blood test holds the promise of saving thousands of lives. Researchers at the Mayo Clinic (Rochester, MN) have found a genetic marker that may be present in patients in danger of dying or becoming disabled from a ruptured aneurysm. Once findings are confirmed, a fast and inexpensive blood test could be developed. The test would be able to screen for genetic variations that indicate a higher than average probability of severe complications from a ruptured aneurysm.

According to The Brain Aneurysm Foundation (Boston), 3–5% of Americans have a brain aneurysm, or a weak bulge on an artery wall of the brain. Although only a small percentage of aneurysms rupture, half of those patients who suffer from a large hemorrhage will die.

Technology such as magnetic resonance imaging and computed tomography can detect an aneurysm, but there isn't a device that can identify an increased risk. Such a tool is important because there are often no signs that a rupture is likely to occur.

Researchers have conducted work revealing the relationship between a molecule known as nitric oxide synthase and the lining of blood vessels, which keeps blood flow running smoothly. They found that when the amount of the molecule increased, the arteries remained relaxed. Subsequent experiments involved comparing the genetic variations in patients with unruptured brain aneurysms to those with ruptured ones. This work helped to establish the function of nitric oxide synthase gene variations in ruptured brain aneurysms. Researchers found that people with certain genetic variations may be about 10 times more likely to experience a ruptured aneurysm. They also discovered strong evidence that the cause of the higher risk level could be the genetic variation.

The team is in the early stages of creating an experimental blood test. It anticipates further studies, which could be conducted on an international scale, to verify its findings.

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