LA Lab Tests for Three Gene Mutations Found to Cause Abnormal Blood Clotting and Miscarriage in Pregnant Women
March 15, 2001
Van Nuys, California -- Reproductive Immunology Associates (RIA) now has the capability to test for three gene mutations that cause abnormal blood clotting and can lead to miscarriage in pregnant women. Called "Inherited Thrombophilias", the disease is comprised of a group of genetic disorders of the blood clotting pathways, leading to abnormal blood clot formation (thrombi). A common route involves resistance to a natural anticoagulant called activated protein C (APC).
Inherited Thrombophilias have been shown in several studies to cause vascular complications that lead to miscarriage, intrauterine fetal death, pre-eclampsia (toxemia of pregnancy), and the HELLP syndrome which is a severe form of pre-eclampsia characterized by hemolysis (blood cells breaking up), elevated levels of liver enzymes, and thrombocytopenia (a low platelet count). According to Dr. William Matzner of RIA, "Women who carry the genes for Inherited Thrombophilias are two to fourteen times more likely than the normal population to have a clotting problem leading to a miscarriage. Our ability to test for this condition is just another way we help couples have successful pregnancies and the families that they so badly want."
The three major gene mutations that lead to Inherited Thrombophilias are:
- Factor V Leiden mutation.
- Factor II (Prothrombin) G20210 gene mutation.
- Methylene-tetrahydrofolate reductase (MTHFR) mutation, leading to hyperhomocytseinemia.
The most common cause of APC resistance arises from the point (one DNA based-pair) mutation at the cleavage site of factor V, called factor V Leiden. It is the most common of the Inherited Thrombophilias, with a prevalence of 10% in the Caucasian population. The mutation has been discovered in 60% of patients who have clot formation during pregnancy, and is also a major cause of blood clots associated with oral contraceptive use. The Prothrombin (factor II) gene mutation has been shown to occur in 7.8% of women who experienced fetal loss due to a clotting disorder. Factor II is one of the major factors in the human clotting pathway. Homocysteine is normally present in low levels in the bloodstream. It is derived from dietary methionine, an amino acid. A gene mutation for the enzyme methylene-tetrahydrofolate reductase (MTHFR), will lead to build up of homocysteine in the bloodstream. This condition, called hyperhomocytseinemia, results in blood clot formation and hardening of the arteries, even in childhood. Nutritional lack of vitamins B6, B12 and folic acid aggravate the problem. Women who have the homozygous form of the MTHFR gene mutation (both of her alleles having the mutation) are more than a two-fold increased risk for a miscarriage. Treatment usually involves a combination of low-dose aspirin plus low molecular weight heparin injections. The therapy is started before pregnancy occurs, and continued four to six weeks after birth. Folic acid supplementation is given to patients with the MTHFR gene mutation.
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