TGFB1 and type 1 diabetes mellitus: The “no association” result between TGF-β1 gene polymorphisms and total IDDM group may imply that the proposed role of TGF-β1 in the induction and development of IDDM might be distal and non-decisive, for example, in comparison to other candidate cytokines, like TNF-α or IFN-γ.