Protrombinémica thrombophilia (Prothrombin thrombophilia) - Gen F2

The protrombinémica thrombophilia is an inherited process affecting blood coagulation, characterized by the formation of blood clots in blood vessels (DVT). These thrombi usually occur more frequently in the lower extremities, but patients are at increased risk of pulmonary embolism. However, most individuals with this genetic base, never develop these thrombi. This process has been linked to miscarriages and increased risk of other complications during pregnancy such as preeclampsia, slow fetal development, or abruption, but nevertheless, most women with this genetic disorder have a normal pregnancy.

Genetic alteration of this process resides in the F2 gene, located on the short arm of chromosome 11 (11p11). This gene encodes prothrombin (coagulation factor II), protein synthesized in the liver and circulates as inactive until a vascular injury occurs, making its active form, thrombin. Thrombin converts fibrinogen to fibrin, the primary protein that forms blood clots. In addition, it is believed that thrombin is involved in growth and cell division, tissue repair and angiogenesis.

The mutation responsible for this disease implies that the gene is increased activity (superactive) causing an excess in the synthesis of prothrombin, which in turn generates excess thrombin which promotes clot formation. The mutation involved in this overactivity of the F2 gene is replaced by guanine nucleotide adenine (G20210A; 20210G> A) in the 3'-noncoding region, which implies a risk of 2.56 times to develop recurrent thrombosis that existing in individuals who have the mutation factor V Leiden. Other factors that increase the risk of blood clots such as: obesity, age, trauma, surgery, smoking, use of oral contraceptives, hormone replacement therapy and pregnancy. The combination of protrombinémica thrombophilia and mutations in other genes involved in blood clotting may also influence risk.

Besides 20210G> A, they described more than 50 mutations in the F2 gene that result prothrombin deficiency. These mutations change an amino acid in prothrombin, which is accompanied by a reduction in activity to varying degrees, which is accompanied by bleeding episodes.

The risk of developing an abnormal clot in a blood vessel depends on whether a person inherits one or two copies of the gene mutation resulting F2 protrombinémica thrombophilia. In the general population, the risk of developing an abnormal blood clot is 1 in 1,000 people a year. F2 inherit a copy of the mutated gene increases the risk of 2 to 3 per 1,000. People who inherit two copies of the mutation, one from each parent, may be at risk of up to 20 per 1,000.

Tests in IVAMI: in IVAMI perform the detection of the G20210A mutation associated with protrombinémica thrombophilia, by amplifying the corresponding exon F2 or gene by the complete PCR amplification of the exons of the F2 gene and subsequent sequencing to detect other types of mutations.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).