Pulmonary embolus has some genetic risk factors
Dr. Keith Roach
Question: I am an active, healthy 70-yearold lady who, out of the blue, was hospitalized with a pulmonary embolus. I had no prior surgeries or leg involvement. After discharge, my GP diagnosed me with Factor V Leiden mutation, heteroz ygous and an elevated homoc ysteine level. I was prescribed folic acid, vitamin B-6 and vitamin B-12 daily. Can you enlighten me further on this issue? — G.K.
Answer: A pulmonary embolus — a blood clot to the lung — is a life-threatening emergency treated with anticoagulants. There are many risk factors for PE, such as surgery, which you men- tioned, but also prolonged immobilization, such as a long plane flight (which is why we recommend getting up and walking around during one).
There are some inherited predispositions for blood clots, and you mention t wo: factor V Leiden and homoc ysteinemia. Factor V Leiden is a common genetic variant (mutation), found in about 5 percent of Caucasian Americans. There are t wo copies of the gene. A person who is heteroz ygous, like you, has one normal and one abnormal copy. This has about a sevenfold risk of abnormal blood clotting. A homozygous person, one with t wo abnormal genes, has about an 80-fold risk of abnormal blood clotting. Although the relative risk is high, the absolute risk still is not high enough to prescribe anticoagulants to treat most people who have a factor V Leiden mutation if they have never had an abnormal blood clot. But this deci- sion should be personalized, with an expert such as a hematologist.
High homocysteine levels can come from a vitamin deficiency or from a different genetic variant, in the MTHFR gene. Having high homocysteine levels can increase your risk of blood clotting by two to three times. Although homocysteine levels usually go down after supplementation with folic acid (and to a lesser extent, vitamins B-6 and B-12), supplementation does not reduce the risk of further blood clots.
Using vitamin supplements is inexpensive and is unlikely to be harmful. Perhaps this is why your doctor recommended the vitamin therapy for you.
Given your unusual situation, I would seek out a consultation with a hematologist who has special expertise in clotting disorders.