Mutations in promoter region of thrombomodulin and venous thromboembolic disease

The present study was designed to analyze the thrombomodulin proximal promo ter region spanning nucleotides - 293 to -12 to search for polymorphisms th at could modify thrombomodulin gene expression in patients with venous thro mboembolic disease. The study population comprised 205 patients and 394 hea lthy subjects of similar age and sex distribution. No polymorphisms and onl y I point mutation (G-33A) were found. The G-33A mutation was present at th e heterozygous state in 2 patients and in 1 control. Being more frequent in the patients (0.97%) than in the controls (0.25%), the C-33A mutation migh t be a risk factor for venous thrombosis. To investigate the effect of this mutation on the thrombomodulin promoter activity, the proximal promoter re gion of the gene (bearing or not bearing the G-33A mutation) was inserted i nto a promotorless expression vector, upstream of the firefly luciferase ge ne, and transiently transfected into EA.hy926 endothelial cells. Under the conditions of the assay, the C-33A mutation mildly decreased the promoter a ctivity. This study confirms that abnormalities of the thrombomodulin proxi mal promoter are not frequent in patients with Venous thromboembolism.