Consequently, it is very important to systematically analyze whether the association with the risk of metabolic diseases and Mn levels is modified by genetic variation in MnSOD, Cu/ZnSOD, and related genes associated with Mn uptake, transport, metabolism, and excretion, such as DMT1, transferrin receptor (TfR), and soluble carrier family (SLC). This evidence concerns the gene SOD2 and metabolic disease.