Those who have the stroke-susceptibility gene have a three to five times greater risk of ischemic stroke, researchers at Reykjavik-based deCODE Genetics said. In ischemic strokes, the flow of blood to the brain is choked, causing cerebral tissue to die.
Details appear Monday in the journal Nature Genetics.
The discovery will not lead to immediate treatments, researchers cautioned. However, the gene, PDE4D, produces an enzyme that can be targeted with drugs, suggesting future therapies are possible.
Swiss pharmaceutical company F. Hoffmann-La Roche Ltd. is already testing such drugs on rats to determine whether they could be used to prevent strokes in humans. The class of drugs is already in use in humans, but for different purposes. The best known of the class is Viagra, prescribed to treat impotence.
deCODE signed a deal worth up to $200 million with Roche in 1998 to look for genes that cause 12 common diseases, including stroke.
The deCODE stroke study involved several hundred people in Iceland who had previously suffered a stroke. The strongest genetic association was found for the gene PDE4D.
Researchers found that there are no variants in the gene itself that are associated with stroke. They did discover that three different proteins made by the gene were produced in lower levels in those affected by the disease, however. That suggests the gene's role in increasing susceptibility to stroke is subtle.
deCODE, set up in 1996 to scour Iceland's gene pool, has amassed a vast amount of information on residents. It says it has mapped genes linked to 25 diseases and isolated genes associated with increased susceptibility to roughly a half-dozen ailments.