Factor V Leiden is a mutation that can cause venous thrombosis. When associated to other risk factors such as the use of contraceptives, important surgical intervention, pregnancy and malignant diseases, the risk for heterozygous carriers increases by three-fold to 10 times or even 80 times for two mutated alleles. The factor V Leiden is found in about 20% of the population with a history of venous thromboembolism. It is present in about 4 to 6% of general population but this percentage changes depending on the ethnicity. This study shows the distribution of alleles in family members of three carriers of factor V Leiden diagnosed with deep venous thrombosis. The mutation investigation of the factor V Leiden gene was performed in 21 family members of 3 heterozygous carriers. The study was performed in the Hematology and Hemotherapy Center from Ceará - Hemoce, Brazil. In this study the V Leiden mutation in its heterozygous form was observed in 83.3% of family 1, 40% of family 2 and 50% of family 3. From the total of 24 members analyzed 50% (12/24) showed the mutation and 66.7% (8/12) did not present the thrombotic disease. An investigation of the factor V Leiden in patients suffering thrombotic events is recommended to explain the etiology and effect of the disease as well as screening of family members so that preventative actions can be adopted.
Factor V Leiden; familial thrombophilias; venous thromboembolism
