ABO blood group genotyping and venous thrombosis in Brazilian women using estrogen
Abstract number: PP-WE-364
Santos1 M.S., Guimar„es1 D.A.M., Paiva1 S.G., Sabino1 A.P., Carvalho1 M.G., Ribeiro2 D.D., Gomes1 K.B., Dusse1 L.M.S., Fernandes1 A.P.
11Clinical and Toxicological Analyses 22Clinical Hospital, Federal University of Minas Gerais, Belo Horizonte, Brazil
How-to-cite Santos MS, Guimar„es DAM, Paiva SG, Sabino AP, Carvalho MG, Ribeiro DD, Gomes KB, Dusse LMS, Fernandes AP. ABO blood group genotyping and venous thrombosis in Brazilian women using estrogen. Journal of Thrombosis and Haemostasis 2009; Volume 7, Supplement 2: Abstract PP-WE-364
Background: Alleles A1 and B of ABO system have been associated with high levels of FVIII, factor von Willebrand and increased risk for VTE, while the O blood group was associated to a lower predisposition to VTE. The aim of this study was to investigate the relationship between genotypes of ABO system and venous thromboembolism in Brazilian women using estrogen (oral contraceptives or hormone replacement therapy).
Methods: ABO polymorphisms were investigated by PCR- RFLP in 40 women that developed VTE and 60 women with no history of VTE (control group). Both groups were under the use of either oral contraceptives (OC) or hormone replacement therapy (HRT). Odds ratio, chi-square or exact Fisher tests were applied for statistical comparisons.
Results: The frequencies of the ABO genotypes among controls were: A1A1(6.94%), A1A2(1.39%), A1O1 (23.61%), A2A2 (1.39%), A2O1 (13.89%), A2O2 (1.39%), BB (1.39%), BO1 (8.33%), O1O1 (38.89%), O1O2 (1.39%) and O2O2(1.39%), which are close to the distribution of these blood groups presented by the general population of Minas Gerais. The frequencies of the ABO genotypes among patients were: A1A1(5.0%), A1A2 (5.0%), A1O1 (22.5%), A1O2 (2.5%), A2A2 (2.5%), A2O1 (7.5%), A1B (10.0%), BB (2.5%), BO1 (20.0%), O1O1 (20.0%) and O1O2 (2.5%). The genotype A1B was more frequent (10%) in patients and not detected in controls, while O1O1 was more present in controls (OR = 0.39 CI = 0.16–0.96 P = 0.04). In addition, the allele O1 was more frequent in the control group (OR = 0.52 CI = 0.30–0.90 P = 0.02) and B (OR = 4.88 CI = 1.85–12.84 P = 0.001) was more frequent in patients. Carriers of non-O blood groups presented higher risk to VTE (OR = 2.46 CI = 1.04–5.82 P = 0.04) by comparing patients and controls. Statistically significant differences were not found for other alleles/genotypes.
Conclusions: These results suggest that non-O blood groups, in specially the B allele, represent important risk factors to the development of VTE among women using HRT or CO.
Disclosure of interest: none declared.