Prevalence of thrombotic risk factors among β-thalassemia patients from Western Iran

Background There is evidence for increased risk of thrombosis in patients with β-thalassemia intermedia and β-thalassemia major. The present study investigated the prevalence of thromboembolic risk factors of prothrombin G20210A, factor V Leiden G1691A and methylentetrahydrofolate reductase (MTHFR) C677T, as well as the hematological and clinical profiles in β-thalassemia major and intermedia patients from Western Iran. Methods Patients consisted of 158 β-thalassemia patients, 151 β-thalassemia major and 7 β-thalassemia intermedia patients, including 82 males and 76 females aged 13.6 ± 6.3 years. The control group were 180 healthy blood donors and school students, consisting of 103 males and 77 females aged 16.8 ± 2.1. Genotyping was done by PCR-RFLP using Mnl I, Hind III and Hinf I for factor V Leiden and prothrombin G20210A and MTHFR, respectively. Results The prevalence of prothrombin G20210A variant in patients and healthy individuals were 1.3 and 3.3%, respectively. Factor V Leiden G1691A was insignificantly higher in β-thalassemia patients (prevalence 5.7% and allele frequency 3.2%) compared to healthy individuals (2.8%). This mutation was found in eight β-thalassemia major (5.3%) and one β-thalassemia intermedia (14.3%) patients. The prevalence of MTHFR C677T polymorphism was slightly higher in patients (50%) compared to healthy individuals (48.3%). Around 71% of β-thalassemia intermedia and 38.4% of β-thalassemia major patients had undergone splenectomy. In β-thalassemia major patients, 5.3% had insulin dependent diabetes mellitus (IDDM) and 6.6% had HCV antibodies. All patients with IDDM were splenectomized and in one of them the prothrombin G20210A variant was found. Two patients, a 7-year-old boy with β-thalassemia intermedia receiving regularly blood transfusion and a β-thalassemia major patient (a 22-year-old splenectomized female), were found to be homozygous for MTHFR 677TT and heterozygous for factor V Leiden G1691A. Double heterozygosity for factor V Leiden G1691A and MTHFR C677T and also homozygous factor V Leiden 1691AA were found in two β-thalassemia major patients. No thromboembolic event has been recorded in the files of patients. Conclusions The results of present study establish the prevalence of biological risk factors of thrombosis in β-thalassemia patients from Western Iran. It seems that thrombophilic mutations may not be associated with thrombotic events in thalassemic patients, which needs to be confirmed by the study of larger sample sizes.