Homocysteine and MTHFR Mutation Resources

MTHFR is the official symbol for the gene “methylenetetrahydrofolate reductase (NAD(P)H).” There are many different mutations in the MTHFR gene. Some individuals with a MTHFR mutation have elevated homocysteine levels. Elevated homocysteine levels may cause irritation of the blood vessels and are considered a risk factor for blood clots. Individuals with MTHFR mutations who have normal homocysteine levels are not at increased risk for clots. Thus, the MTHFR mutation by itself is not a clotting disorder.

Signs and Symptoms of Blood Clots – What You Need to Know

If you have the MTHFR mutation with elevated homocysteine levels and you are at risk of blood clots, you need to be aware of the symptoms of DVTs (Deep Vein Thrombosis or leg or arm clot) so you can seek medical attention.

If you have a Deep Vein Thrombosis or DVT you will notice:

  • Pain or tenderness in your arm or leg – often described as a cramp or Charlie horse – with one or more of the following:

    • Swelling
    • Red or purple skin color
    • Warm to the touch

    If a piece of a DVT breaks off and travels to the lung, it can cause a lung clot. We call this a pulmonary embolism or PE. A PE can be a life threatening medical emergency. You need to seek immediate medical attention if you have symptoms of a PE.

    If you have a Pulmonary Embolism or PE (lung clot), you may experience:

    • Difficulty breathing or shortness of breath
    • Chest pain– especially when trying to breathe
    • Rapid or racing heart beat
    • Fainting or passing out
    • Coughing up blood

    Resources for More Information

    You can find more information about the MTHFR mutation with elevated homocysteine levels at these links below:

    1. MTHFR (2011) Genetics home reference


    2. Homocysteine and MTHFR Mutations Relation to Thrombosis and Coronary Artery Disease (2005)


    Patient Stories of the MTHFR mutation with elevated homocysteine and other causes of elevated homocysteine levels in their own voices:

    You can read about people with MTHFR mutation with elevated homocysteine and other causes of elevated homocysteine levels & blood clots

    Patient Stories in Their own Voices

    Jessica Stanley’s Blood Clot Story

    Laura Zain’s Journey with Kyle

    January 2014

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