Short CommunicationHyperhomocysteinemia increases the risk of venous thrombosis independent of the C677T mutation of the methylenetetrahydrofolate reductase gene in selected Brazilian patientsMorelli, V. M.; Lourenço, D. M.; D'Almeida, V.; Franco, R. F.; Miranda, F.; Zago, M. A.; Noguti, M. A. E.; Cruz, E.; Kerbauy, J.Author Information V. M. Morelli, D. M. Lourenço, M. A. E. Noguti and J. Kerbauy are with the Department of Clinical Medicine, V. D'Almeida and E. Cruz are with the Department of Paediatrics and F. Miranda is with the Department of Surgery, Federal University of São Paulo (UNIFESP), São Paulo, Brazil; and R. F. Franco and M. A. Zago are with the Department of Clinical Medicine, School of Medicine of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, Brazil. (Received 30 July 2001; revised 26 November 2001; accepted 4 December 2001) Sponsorship: This work was partly supported by FAPESP (1998/13218-2). Address correspondence to Vânia M. Morelli, M.D., Division of Hematology, Department of Clinical Medicine, Federal University of São Paulo (UNIFESP), Rua Botucatu 740, CEP 04023-900 São Paulo SP, Brazil. Tel: (+55) 11 55 76 42 40; fax: (+55) 11 55 71 88 06; e-mail: firstname.lastname@example.org Blood Coagulation & Fibrinolysis: April 2002 - Volume 13 - Issue 3 - p 271-275 Buy Abstract Fasting total homocysteine (tHcy) and the methylenetetrahydrofolate reductase (MTHFR) C677T mutation were evaluated in 91 patients with venous thromboembolism and without acquired thrombophilia, and in 91 age-matched and sex-matched controls. Hyperhomocysteinemia was detected in 11 patients (12.1%) and in two controls (2.2%), yielding an odds ratio (OR) for venous thrombosis of 6.1 [95% confidence interval (CI), 1.3–28.4]. After excluding 21 patients and four controls with other known genetic risk factors for venous thrombosis, the OR was not substantially changed (7.0; 95% CI, 1.5–33.1). The prevalence of the MTHFR 677TT genotype was not significantly different in patients (9.9%) and in controls (5.5%), with an OR for venous thrombosis of 1.8 (95% CI, 0.6–5.8). Subjects with the MTHFR 677TT genotype showed higher levels of tHcy compared with the 677CC genotype in patients (P = 0.010) and in controls (P = 0.030). In conclusion, we found that fasting hyperhomocysteinemia is a risk factor for venous thrombosis in patients without known acquired thrombophilia and other genetic risk factors for venous thrombosis. Although tHcy levels are significantly higher in those homozygous for the MTHFR C677T mutation, this genotype does not increase the thrombotic risk in our study population. © 2002 Lippincott Williams & Wilkins, Inc.