fa قلب Heart پژوهشي Research <p style="text-align: justify;"><strong>Background:</strong> The most common polymorphisms identified in the Methylenetetrahydrofolate reductase (MTHFR) gene, C677T and A1298C lead to defective activity of this enzyme and increase the risk of venous and arterial thrombosis. There are limited investigations regarding the effects of thrombogenic polymorphisms on the clinical phenotypes of rare hereditary hemorrhagic disorders like Glanzmann&#39;s thrombasthenia (GT) and<br> the exact correlation between MTHFR polymorphisms and GT is not well established. This calls for further studies in populations with a large number of such patients. So, this study was performed to question whether coinheritance of MTHFR polymorphisms and GT can modulate the clinical phenotype of GT.<br> <strong>Material and Methods:</strong> In the present case-control study which performed at Pathology and Stem Cell Research Center at Kerman University of Medical Sciences, 65 patients with GT and 100 normal voluntary blood donors as the control group were evaluated. The mean (SD) age of patients and the control group were 2.33&plusmn;1.54 years (range 0-5 years) and 2.6&plusmn;1.72, respectively. The detection of MTHFR C677T and A1298C polymorphisms was carried out using a Polymerase Chain Reaction- Restriction Fragment Length Polymorphism (PCR-RFLP) method. In accord with the Glanzmann&#39;s Thrombasthenia Italian Team (GLATIT) Protocol, the clinical severity of bleeding in patients with GT was determined. Two tests of descriptive statistics (i.e. frequencies) and Chi-square, using the SPSS version 19, were employed to analyze the data.<br> <strong>Results:</strong> Based on results, there were no significant statistical differences in the prevalence of the MTHFR C677T polymorphism (P=0.703) or the MTHFR A1298C polymorphism (P=0.187) between patients and the control group. In addition, no association between the severity of bleeding and these polymorphisms was found (P=0.385).<br> <strong>Conclusions:</strong> It was concluded that the thrombogenic mutations of MTHFR do not solely modulate the severity of clinical symptoms in patients with GT.</p> Glanzmann's thrombasthenia, Polymorphism, Methylenetetetrahydrofolate reductase, Rare hereditary bleeding disorders 48 56 http://ijpho.ssu.ac.ir/browse.php?a_code=A-10-70-112&slc_lang=fa&sid=1 Shima Kazemzadeh No Department of Laboratory Hematology and Blood Banking, Faculty of allied medicine, Kerman University of Medical Sciences, Kerman, Iran. Rezvan Mohammadi No Pathology and Stem Cell Research Center, Kerman University of Medical Sciences, Kerman, Iran. Fatemeh Shadkam Farokhi No Pathology and Stem Cell Research Center, Kerman University of Medical Sciences, Kerman, Iran. Alireza Shafiian No School of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran. Mohammad Faranoush No Pediatric growth and development research center, Endocrinology institute, Iran university of medical science, Tehran, Iran. Alireza Farsinejad Yes Pathology and Stem Cell Research Center, Kerman University of Medical Sciences, Kerman, Iran Fereydoun Ala No Professor of Hematology, Iranian Comprehensive Hemophilia Care Centre, Tehran, Iran.