Patient Education Blog

What Causes Clots? – A Family Study


It is known that the risk for blood clots in the leg (DVT) and lung (PE) is partly inherited. Some genes that increase the risk for DVT and PE are known (e.g. factor V Leiden, the factor II 20210 mutation, protein, protein C, S and antithrombin mutations). However, it is suspected that many other and, as yet, unidentified genes also increase the risk for DVT and PE. One of the ways to discover such clotting genes is by studying families.

Ongoing Study

A study is presently ongoing at the Mayo Clinic in Rochester, MN,  that is investigating what genes put people at risk for clots (DVT and PE). The study is headed by Dr. John Heit, a well established and respected clinician and researcher. He is looking  for families who want/are willing to participate in finding causes for blood clots. Of course, the study is approved by the Mayo IRB (Institutional Review Board = Ethics Committee).

Dr. Heit is specifically looking for the following types of families:

  1. Strong Family History of clots: Families in which 3 or more blood-related family members have had blood clots (a DVT or  PE), (b) are alive, and (c) available to provide a blood or saliva sample in the future.
  2. Families in which at least one person had a clot (DVT or PE) and that person has a living brother or sister (who has not had a clot). In research terms, this is called an “affected-unaffected sib-pair”.
  3. Families in which at least one person had a clot (DVT or PE) and both parents of that person are still living (and did not have a clot). In research terms, this is called a  Trio” (consisting of an affected child and the child’s parents).

What you can Do

I would encourage interested individuals/families to visit Dr. Heit’s website to participate in the study. No visit at the Mayo Clinic is needed. The web-based family history questionnaire would need to be filled out. Dr. Heit would then contact you (and/or your family member) and a blood and/or saliva sample would have to be sent to him to be used for laboratory genetic testing.  ClotConnect would like to encourage patients/families to participate in this study – it is an important study; and we all need to  learn more about what causes clots.

Disclosure: I have no financial conflict of interest with this post.

Last updated: July 9th, 2012

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3 Responses to “What Causes Clots? – A Family Study”

  1. Linda Anglebrandt says:

    This is a prayer answered! My grandfather died from PE, my sister had 1 PE event & survived, my son died at 19 from multiple PE, 5 out of 8 of my siblings have had clotting issues!Hoping they will participate.

  2. monte mishoe says:

    First of all I would like to thank you for making this website which contains a lot of great information on it. I had a question about the research that Dr. Heit was conducting for the family study. Is it still going on? The reason why I ask is because I tried to click on the link and it would not bring me to the questionaire site. If it is can you provide me with the website that I can go to.


    Monte Mishoe