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Posted: 10:11 AM Nov 4, 2006
Stroke Warning
Study looks for genetic map Imagine a childhood screening test that could help you prevent a stroke in adulthood. It's not far-fetched.
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Imagine a childhood screening test that could help you prevent a stroke in adulthood. It's not far-fetched.
Ofelia Rohan-Gentry never thought she’d have a stroke. At age 33, she did.
“You really think that you're invincible and nothing like that will ever happen to you,” she says.
It could have been prevented with proper warning.
Researchers at the University of Maryland say that a genetic test could one day be possible that will provide that warning.
Dr. John W. Cole says, "That’s what the focus of this current study was. It looked at a specific gene called phosphodietsterase 4d.”
PDE4D has been linked to strokes in older men. Now new findings show certain variations of the gene also increase stroke risk in young women.
Dr. Cole says, "The strongest variant that was associated with stroke when we sort of did a breakdown of it by different risk factors, it turned out that the risk was mediated in smokers.”
In other words, smoking is already bad for you. If you also have the gene variant, your risk for a stroke goes even higher.
Dr. Cole says, "If you had this, this one specific variant and you are not a smoker or former smoker, it didn’t really seem to increase your risk.”
Understanding the interaction between your genetic makeup and stroke risk factors could lead to new ways to prevent a future stroke, "either a test, genetic test, to look for variants within this gene that might make people more prone to stroke or potentially develop a drug that may be, might be able to block these effects,” Dr. Cole says.
Until then, the only thing to do is control stroke risk factors. Besides smoking, they include diabetes, high cholesterol, high blood pressure, poor diet and a sedentary lifestyle.
The study shows that, depending on the genetic variation, a young woman's risk for stroke can increase as much as 50 to 100 percent. Out of every five people who die from a stroke, three are women. The genetic studies are still in progress.
Fast Facts:
Stroke
A stroke occurs when a part of the brain is deprived of oxygenated blood, causing the brain cells in the affected area to die. There are two main types. Ischemic strokes are caused by a blockage in a blood vessel feeding the brain. A blood clot may form in a cerebral artery and block the flow of blood. This is called a cerebral thrombosis. A blood clot can also form in another part of the body, break loose and travel through the circulatory system, where it becomes trapped in a narrower artery of the brain. This is called a cerebral embolism. Ischemic strokes are the most common form of stroke, accounting for about 88 percent of all cases.
The second type, hemorrhagic stroke, is caused when a blood vessel in the brain ruptures. Although this kind of stroke is less common, it is often more deadly. Loss of blood flow causes the affected areas to die. In addition, as the blood fills the space, it puts pressure on surrounding brain tissue and can cause even more damage.
According to the American Heart Association, about 700,000 strokes occur each year in the U.S. Stroke kills about 157,000 Americans each year and is the third leading cause of death from disease. It is also the leading cause of serious long-term disability. This year, treatments for stroke and loss of function will cost this country about $57.9 billion.
Risk of Stroke in Women
Several risk factors have been identified for stroke. Family history of the disease, high blood pressure, high cholesterol, smoking, diabetes, excess weight and a sedentary lifestyle can increase the risk of stroke for everyone. However, women also appear to have some unique risk factors not seen in men:
Pregnancy. During pregnancy, blood pressure increases, the heart works harder and women’s bodies have higher levels of blood-clotting factors.
Hormone replacement therapy. Hormones, especially the combined use of estrogen and progestin, are associated with an increased risk for stroke and heart attack.
Thick waist and high triglyceride levels. The National Stroke Association reports that women with a waist of 35.2 inches or larger and a triglyceride level of 128 mg/L or higher have a five-fold increased risk for stroke.
Migraines. Women who have migraine headaches are 3 to 6 times more likely to have a stroke. Women who smoke, take oral contraceptives and have migraines increase their risk of stroke by up to 34 times.
Genetics and Stroke Risk
Researchers at the University of Maryland School of Medicine are studying genetic risk factors for stroke in young women (15 to 49). Using data from the “Stroke Prevention in Young Women Study 2,” investigators honed in on a specific gene previously linked to stroke risk, named phosphodietsterase 4D (PDE4D).
The investigators looked at two dozen variations (called polymorphisms) in the PDE4D gene. Five of those variations were found to be associated with an increased stroke risk. Of greater importance, one particular variant was strongly influenced by smoking. Women who smoke and had the gene variant had a significantly increased risk for stroke. In addition, the more cigarettes smoked, the higher the risk. The gene variant didn’t appear to have any stroke association in non-smokers or former smokers.
John W. Cole, M.D., Neurologist, says, in the future, if more specific genetic factors can be pinpointed, researchers may one day be able to develop a blood test that identifies personal risk for stroke. Patients that are found to carry “at-risk” genes may be able to take steps to reduce the influence of environmental or lifestyle factors that can contribute to stroke risk.
Web Resources:
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