TNF and sarcoidosis: Of these studies, 12 articles examined the association of the TNF-α gene G-307A polymorphism with sarcoidosis [7-17,19]; five articles focused on the TNF-α gene G-238A polymorphism [10,12,14,15,17]; four articles focused on the TNF-α gene C-857T polymorphism [14,15,17,18]; three articles focused on the TNF-α gene T-1031C and C-863A polymorphisms [14,15,17]; three articles focused on the TNF-β gene A252G polymorphism [13,14, 16].