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