MTHFR Gene and risk of Stroke

Strokes occur when blood flow to the brain stops, leading to death of brain cells within minutes. An Ischemic stroke, is the type caused by a blood clot that blocks a blood vessel in the brain and a hemorrhagic stroke, is caused by a blood vessel that breaks and bleeds into the brain. "Mini-strokes" or transient ischemic attacks (TIAs), occur when the blood supply to the brain is briefly interrupted.

Modifiable risk factors for stroke include: An unhealthy diet, Obesity, Physical inactivity, Cigarette smoking, High blood pressure, Diabetes, Heart disease and high cholesterol. Non modifiable risk factors include: Age - More common after 55 years of age; Gender - More common in men than women; Race - African Americans are at a higher risk for strokes than Caucasians; Family history - More common if a close family member has had a stroke. Epidemiological studies have also linked elevated homocysteine with an increased risk of stroke.4

The MTHFR gene provides instructions for making an enzyme called methylenetetrahydrofolate reductase. This enzyme is involved in a multistep process that converts the amino acid homocysteine to another amino acid, methionine. Mutations of the MTHFR gene leads to the production of a nonfunctional version of the enzyme. Without the functional enzyme, homocysteine cannot be converted to methionine, leading to a build up of homocysteine. Elevated levels of homocysteine have been shown to be an independent risk factor for ischemic stroke, thrombotic and cardiovascular diseases. 1