GGT7 and type 2 diabetes mellitus: Thus, the associations of GGT7 and GSS gene polymorphisms with the levels of glutathione and ROS show that the genes have the potential to impact the glutathione homeostasis and loss-of-function effects of their alleles, may contribute to the reduced synthesis of glutathione in the cell, and may play a role in the pathogenesis of type 2 diabetes.