Acessibilidade / Reportar erro

Increased risk of venous thrombosis by AB alleles of the ABO blood group and Factor V Leiden in a Brazilian population

Abstract

Most cases of a predisposition to venous thrombosis are caused by resistance to activated protein C, associated in 95% of cases with the Factor V Leiden allele (FVL or R506Q). Several recent studies report a further increased risk of thrombosis by an association between the AB alleles of the ABO blood group and Factor V Leiden. The present study investigated this association with deep vein thrombosis (DVT) in individuals treated at the Hemocentro de Pernambuco in northeastern Brazil. A case-control comparison showed a significant risk of thrombosis in the presence of Factor V Leiden (OR = 10.1), which was approximately doubled when the AB alleles of the ABO blood group were present as well (OR = 22.3). These results confirm that the increased risk of deep vein thrombosis in the combined presence of AB alleles and Factor V Leiden is also applicable to the Brazilian population suggesting that ABO blood group typing should be routinely added to FVL in studies involving thrombosis.

ABO blood group; Factor V Leiden; venous thrombosis


HUMAN AND MEDICAL GENETICS

SHORT COMMUNICATION

Increased risk of venous thrombosis by AB alleles of the ABO blood group and Factor V Leiden in a Brazilian population

Magaly B.P.L.V. LimaI; Aldemir Branco de Oliveira-FilhoI; Júlia F. CamposII; Fárida C.B.C. MeloII; Washington Batista das NevesII; Raul Antônio Morais MeloII; José Alexandre Rodrigues LemosI, III

ILaboratório de Biologia Celular e Molecular, Fundação Centro de Hemoterapia e Hematologia do Pará, Belém, PA, Brazil

IILaboratório de Biologia Molecular, Fundação Centro de Hematologia e Hemoterapia de Pernambuco, Recife, PE, Brazil

IIIInstituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brazil

Send Correspondence to Send Correspondence to: José Alexandre R. Lemos Centro de Hemoterapia e Hematologia do Pará Travessa Padre Eutíquio 2109 66033-000 Belém, PA, Brazil E-mail: lemos@ufpa.br

ABSTRACT

Most cases of a predisposition to venous thrombosis are caused by resistance to activated protein C, associated in 95% of cases with the Factor V Leiden allele (FVL or R506Q). Several recent studies report a further increased risk of thrombosis by an association between the AB alleles of the ABO blood group and Factor V Leiden. The present study investigated this association with deep vein thrombosis (DVT) in individuals treated at the Hemocentro de Pernambuco in northeastern Brazil. A case-control comparison showed a significant risk of thrombosis in the presence of Factor V Leiden (OR = 10.1), which was approximately doubled when the AB alleles of the ABO blood group were present as well (OR = 22.3). These results confirm that the increased risk of deep vein thrombosis in the combined presence of AB alleles and Factor V Leiden is also applicable to the Brazilian population suggesting that ABO blood group typing should be routinely added to FVL in studies involving thrombosis.

Key words: ABO blood group, Factor V Leiden, venous thrombosis.

Deep vein thrombosis (DVT) is one of the main clinical manifestations of venous thromboembolism (VTE). DVT is a multi-factorial disorder caused by genetic and/or acquired abnormalities of the hemostatic mechanism, resulting in hypercoagulation (Dahlbäck, 2003; Dahlbäck and Villoutrex, 2003). Hereditary thrombophilia is responsible for most cases of predisposition to VTE and the greatest prevalence is of a resistance to activated protein C (Svensson and Dahlbäck, 1994), caused in most cases by a point mutation in the gene of the coagulation factor V (FV), known as Factor V Leiden (FVL), FV: R506Q or FV: G1691A. (Bertina et al., 1994). FV is a plasma glycoprotein of 330 kDa, formed by 2196 amino acids and coded by a gene with 25 exons located in chromosome region 1q21-25 (Wang et al., 1988; Cripe et al., 1992). In its activated form (FVa), it participates in the prothrombinase complex of the coagulation cascade as an essential co-factor to factor Xa in thrombin genesis. FV is also a proteolytic target for activated protein C (APC), which exercises its anti-coagulant function by deactivating it. The deactivated FV and protein S act as co-factors of APC, deactivating the factor VIII (FVIII) molecule (Dahlbäck and Villoutrex, 2003). The R506Q mutation occurs in exon 10 of the FV gene and is characterized by a G → A transition at nucleotide 1691, which results in a change from Arginine to Glutamine (Arg → Gln) at position 506 in the amino acid sequence (Bertina et al., 1994). The main consequence of this mutation is the loss of one of the cleavage sites, which makes FVa partially resistant to the proteolytic degradation of APC. This flaw in the anticoagulation mechanism mainly results in high FVIII and trombin levels, thereby increasing the risk of VTE due to the installation of a state of hypercoagulability (Franco and Reitsma, 2001).

The AB alleles of the ABO blood group, high FVIII levels and von Willebrand factor (vWF) have been associated to a risk of venous thrombosis (Jick et al., 1969; Koster et al., 1995; Tirado et al., 2005). A number of reports reveal that individuals with the AB genotype have higher FVIII and vWF levels than those with the O genotype (Preston and Barr, 1964; Orstavick et al., 1985; Gill et al., 1987; Kamphuisen et al., 1998). Studies have also reported that the association between the R506Q allele and AB alleles increases the risk of thrombosis (Robert et al., 2000; Morelli et al., 2005; Biron-Adréani et al., 2006; Ohira et al., 2007). The present study investigated the relationship between DVT and the association of AB genotypes and the R506Q allele in the population of the state of Pernambuco in northeastern Brazil.

Sixty-five patients participated in the study (47 females and 18 males) with a mean age of 34 years (range 6-67 years) and no familial relationships to one another. All patients had a history of DVT and were treated at the outpatient clinic of the Fundação HEMOPE (Pernambuco, Brazil) between 2001 and 2006. An additional 51 individuals from the same state and with no history of DVT were selected for the control group, which was paired for gender and age group and had no family relationships to one another or to the patients. All samples were collected following the informed consent of the participants.

Peripheral venous blood samples were collected in a sterile vacutainer tube containing EDTA as the anticoagulant. Genomic DNA was extracted and purified from leukocytes using the GFX genomic DNA purification kit (Amershan Pharmacia Biotech), following the manufacturer's instructions. Genotyping of the ABO system and detection of the R506Q allele in the patients and controls were performed through real-time polymerase chain reaction/allelic discrimination assay using the ABI PRISM 7000 Sequence Detection System (SDS). For the amplification reactions, the Taqman Universal PCR Master Mix (Applied Biosystems, Foster City, CA) set of reagents was used together with a set of primers and specific probes for the differentiation between the O and A or B genotypes and differentiation between wild alleles and R506Q, designed and synthesized by the Assays-by-Design service (Part Number 4331349) from the sequences of interest sent to Applied Biosystems. In the text and Tables, the genotype designation O refers to absence of any A or B alleles at the ABO locus and AB refers to any of the following: AA, AO, AB, BB, or BO.

Following amplification, the fragments were discriminated by fluorescent data analysis through the software program (version 1.1) on the ABI PRISM 7000 SDS equipment. Statistical analysis was performed by univariate analysis, using the Bioestat 4.0 program (Ayres et al., 2005). Confidence limits were set at 95% and exact p values determined using Pearson's Chi square.

The frequencies of patients and controls, ABO and FVL genotypes and Odds Ratios of increased risk of DVT are displayed in Table 1.

We have assumed that all or the majority of FVL (+) individuals were heterozygotes and carried only a single mutant allele, which is a reasonable assumption given the allele frequency of between 0.02-0.05 seen in many populations. In the patient group, 29.3% had the R506Q allele, whereas only 3.9% in the control group. This led to a highly significant risk of DVT (OR = 10.1; 95%CI = 2.23-45.9; p = 0.0004) which was higher than that described in the study by Morelli et al. (2005), which was 7.9. This risk was increased further in individuals with the AB/FVL(+) genotype combination (OR = 22.3; 95%CI = 2.68-185.7; p = 0.0002) These results are compatible with all previous investigations on the combined additive contribution of ABO and FVL genotypes to DVT. The results of previously published studies are summarized in Table 2. All studies demonstrate the added risk of AB alleles which approximately doubles the risk imparted by FVL. The differences in ORs between studies are probably explicable on small sample sizes and ethnic or chance differences in observed ABO and FVL allele frequencies. The exact mechanism through which the AB alleles influence the risk of thrombosis is not yet well clarified. However, evidence suggests that it could be explained by the effect of the ABO locus on the rise in plasma levels of FVIII (Morelli et al., 2005), likely due to a lower catabolism of the vWF (Gill et al., 1987). The presence of oligosaccharides with A, B and O structures in the human vWF molecule support this hypothesis (Sodetz et al., 1979; Matsui et al., 1992). In individuals with the FVL who have the AB genotype, the weak deactivation of FVIII in combination with high levels of this factor through the influence of the ABO genotype are thought to result in an exponential increase in the risk of developing VTE (Morelli et al., 2005; Váradi et al., 1996).

The present study confirms that the association of a combined increased risk of AB alleles and FVL to deep vein thrombosis is also applicable to the population of North Eastern Brazil. We propose that ABO genotyping should be carried out routinely in combination with FVL to evaluate risk for DVT. It would also be of great interest to study whether ABO alleles also have an additive affect in other situations, such as spontaneous abortion or reduced menopausal age, where FVL has also been claimed to play a role.

Acknowledgments

We thank Fundação HEMOPE, especially Raul Melo, Fárida Melo, Alita Azevedo and the staff members who collaborated as the control group.

Received: October 13, 2008; Accepted: January 27, 2009.

Associate Editor: Peter L. Pearson

  • Ayres M, Ayres Jr M, Ayres DM and Santos AS (2005) BioEstat 4.0 Aplicações Estatísticas nas Áreas das Ciências Biológicas e Médicas. Sociedade Civil Mamirauá, Belém, 324 pp.
  • Bertina RM, Koeleman BPC, Koster T, Rosendaal FR, Dirven RJ, de Ronde H, van der Velden PA and Reitsma PH (1994) Mutation in blood coagulation factor V associated with resistance to activated protein C. Nature 369:64-70.
  • Biron-Adreani C, Morangi P-E, Le Havre R, Le Cam-Duchez V, Borg J-E, Saladin-Thiron C, Bauters A, Jude B, Aillaud M-F, Juhan-Vague I et al. (2006) ABO blood group but not haemostasis genetic polymorphisms significantly influence thrombotic risk: A study of 180 homozygotes for the Factor V Leiden mutation. Br J Haematol 135:697-702.
  • Cripe LD, Moore KD and Kane WH (1992) Structure of the gene for human coagulation factor V. Biochemistry 31:3777-3785.
  • Dahlbäck B (2003) The discovery of activated protein C resistance. J Thromb Haemost 1:3-9.
  • Dahlbäck B and Villoutrex BO (2003) Molecular recognition in the protein C anticoagulant pathway. J Throm Haemost 1:1524-1534.
  • Franco RF and Reitsma PH (2001) Genetic risk factors venous thrombosis. Hum Genet 109:369-384.
  • Gill JC, Endres-Brooks J, Bauer PJ, Marks WJ and Montgomery RR (1987) The effect of ABO blood group on the diagnosis of von Willebrand disease. Blood 69:1691-1695.
  • Jick H, Westerholm B, Vessey MP, Lewis GP, Stone D, Inman WHW, Shapiro S and Worcester J (1969) Venous thromboembolic disease and ABO blood type. A cooperative study. Lancet 1:539-542.
  • Kamphuisen PW, Howing-Duistermaat JJ, Van Houwelingen HC, Eikenboom JCJ, Bertina RM and Rosendaal FR (1998) Familial clustering of factor VIII and von Willebrand factor levels. J Thromb Haemost 79:323-327.
  • Koster T, Blann AD, Vandenbrouck JP and Rosendaal FR (1995) Role of clotting factorVIII in effect of von Willebrand factor on occurrence of deep-vein thrombosis. Lancet 345:152-155.
  • Matsui T, Titani K and Mizuoch T (1992) Structures of the asparagine-linked oligosaccharide chains of human von Willebrand factor: Ocurrence of blood group A, B and H structures. J Biol Chem 267:8723-8731.
  • Morelli VM, De Visser MCH, Vos HL, Bertina RM and Rosendaal FR (2005) ABO blood group genotypes and the risk of venous thrombosis: Effect of factor V Leiden. J Thromb Haemost 3:183-185.
  • Ohira T, Cushman M, Tsai MY, Zhang Y, Heckbert SR, Zakai NA, Rosamond WD and Folsom AR (2007) ABO blood group, other risk factors and incidence of venous thromboembolism: The Longitudinal Investigation of Thromboembolism Etiology (LITE). J Thromb Haemost 5:1455-1461.
  • Orstavick KH, Magnus P, Reisner H, Berg K, Grahan JB and Nance W (1985) Factor VIII and Factor IX in a twin population. Evidence for a major effect of ABO locus on factor VIII level. Am J Hum Genet 37:89-101.
  • Preston AE and Barr A (1964) The plasma concentration of factor VIII in the normal population. Br J Haematol 10:238-245.
  • Robert A, Aillaud MF, Eschwege V, Randrianjohany A, Scarabi Y and Juhan-Vague I (2000) ABO blood group and risk of venous thrombosis in heterozygous carriers of factor V Leiden. J Thromb Haemost 83:630-631.
  • Sodetz JM, Paulson JC and McKe PA (1979) Carbohydrate composition and identification of blood groups A, B and H oligosaccharide structures on human Factor VIII/von Willebrand factor. J Biol Chem 254:10.754-10.760.
  • Svensson PJ and Dahlbäck B (1994) Resistance to activated protein C as a basis for venous thrombosis. N Engl J Med 330:517-522.
  • Tirado I, Mateo J, Soria JM, Oliver A, Martinez-Sànchez E, Vallvé C, Borrell M, Urrutia T and Fontcuberta J (2005) The ABO blood group genotype and factor VIII levels as independent risk factors for venous thromboembolism. Thromb Haemost 93:468-474.
  • Váradi K, Rosing J,Tans G, Pabinger I, Keil B and Schwarz HP (1996) Factor V enhances the cofactor function of protein S in the APC-mediated inactivation of factor VIII: Influence of the factor V R506Q mutation. J Thromb Haemost 76:204-208.
  • Wang H, Riddell DC, Guinto ER, McGillvray RTA and Hamerton JL (1988) Localization of the encoding human factor V to chromosome 1q21-25. Genomics 2:324-328.
  • Send Correspondence to:

    José Alexandre R. Lemos
    Centro de Hemoterapia e Hematologia do Pará
    Travessa Padre Eutíquio 2109
    66033-000 Belém, PA, Brazil
    E-mail:
  • Publication Dates

    • Publication in this collection
      25 May 2009
    • Date of issue
      2009

    History

    • Received
      13 Oct 2008
    • Accepted
      27 Jan 2009
    Sociedade Brasileira de Genética Rua Cap. Adelmio Norberto da Silva, 736, 14025-670 Ribeirão Preto SP Brazil, Tel.: (55 16) 3911-4130 / Fax.: (55 16) 3621-3552 - Ribeirão Preto - SP - Brazil
    E-mail: editor@gmb.org.br