H63D genetic defect linked to increased risk of stroke

One of the most common genetic defects passed on through families significantly increases a person's chance of having a stroke, according to a study published in the March 27, 2007, issue of Neurology, the scientific journal of the American Academy of Neurology.

Researchers evaluated 9,178 people in Denmark for 24 years, during which 393 people had a stroke and 504 people developed cerebrovascular disease.

All of the participants were screened for having the H63D genetic defect in the HFE gene, which is also known as the hemochromatosis gene. It is one of the most common inheritable genetic defects, especially in Europe, where it's estimated one out of four people carry the defective gene in northern Europe. In southern Europe, even more people may carry this genetic defect. Hemochromatosis leads to iron overload in the body, eventually causing organ dysfunction, diabetes, and liver cirrhosis.

The study found people with two copies of the H63D genetic defect were two to three times more likely to develop stroke than those without the gene.

"This type of gene has previously been associated with brain diseases such as Alzheimer disease, Parkinson disease, ALS, multiple sclerosis, and cerebrovascular disease, but this is the first time we've been able to determine this gene predicts such a significant increased risk of stroke," said study author Borge G. Nordestgaard, MD, DMSc, with Herlev University Hospital in Copenhagen, Denmark.

The study found the gene was not associated with carotid atherosclerosis, which is a disease involving the hardening of arteries in the head and neck through plaque build-up.

"Further research is needed to determine why this gene appears to cause such a significant increased risk of stroke, since our data suggests plaque build-up in the arteries and iron overload are not to blame," said Nordestgaard as well as study author Christina Ellervik, MD, also with Herlev University Hospital.

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