Thepresent study was conducted to evaluate serum Hcy as a serological marker forthe assessment of the activity of BD with respect to specific individual clinical manifestations.Serum levels of Hcy were compared with the values of C-reactive protein (CRP),an acute phase reactant, the erythrocyte sedimentation rate (ESR), and tumornecrosis alpha (TNF-α) which is an important proinflammatory cytokine. This evidence concerns the gene TNF and Behcet disease.