title: Increased Factor V Leiden frequency is associated with venous thrombotic events among young Brazilian patients.
abstract: BACKGROUND
  Of the inherited thrombophilias, the Factor V Leiden (FVL) and the prothrombin mutant (FII G20210A) are associated with increased risk of venous thromboembolism (VTE). The C677T mutation of the methylenetetrahydrofolate reductase gene, which may lead to hyperhomocysteinemia, is also considered a risk factor for VTE in some studies. However, the frequency of these genetic risk factors may vary significantly among different populations.
  
  
  METHODS
  The FVL, FII G20210A and C677T mutations were investigated by PCR-RFLP in 275 young VTE Brazilian patients as well as in 324 biologically unrelated individuals selected to compose the control group.
  
  
  RESULTS
  The C677T mutation in the MTHFR gene was detected in 135 (49.1%) patients, of which 117 (42.5%) were identified as heterozygous and 18 (6.5%) as homozygous. The G20210A mutation was detected in 14 (5.1%) patients in heterozygosis. In both cases, no significant difference was observed when these results were compared to the frequencies observed in the control group. FVL was detected in heterozygosis in 19 (6.9%) patients, corresponding to a significantly increased frequency when compared to that observed for the control group (1.2%) (OR 5.9; 95% CI 2.08-16.79; p < 0.001).
  
  
  CONCLUSIONS
  The data indicated that FVL is significantly associated with VTE among young Brazilian patients, but also supported previous evidence that VTE is a multi-factorial disease, resulting from the interaction of genetic and acquired risk factors.
authors.affiliation: Faculdade de Farmácia, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Adriano
authors.initials: A
authors.lastname: de Paula Sabino
authors.forename: Daniela Amorim Melgaço
authors.initials: DA
authors.lastname: Guimarães
authors.forename: Daniel Dias
authors.initials: DD
authors.lastname: Ribeiro
authors.forename: Sabrina Guimarães
authors.initials: SG
authors.lastname: Paiva
authors.forename: Luci Maria
authors.initials: LM
authors.lastname: Sant'Ana Dusse
authors.forename: Maria
authors.initials: M
authors.lastname: das Graças Carvalho
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Fernandes
mesh_terms: D000328:Adult; D000367:Age Factors; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D005165:Factor V / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011516:Prothrombin / Q000235:genetics; D020246:Venous Thrombosis / Q000208:ethnology / Q000235:genetics*
chemical_list: C095381:factor V Leiden; D005165:Factor V; D011516:Prothrombin; D042965:Methylenetetrahydrofolate Reductase (NADPH2)