GGCT and type 2 diabetes mellitus: Meanwhile, a limited number of studies, a significant proportion of which were carried out by our research team, looked into the link between T2D and genetic variations in glutathione-metabolizing enzymes such as glutamate cysteine ligase, glutathione synthetase, glutathione reductase, gamma-glutamyl cyclotransferase, and gamma-glutamyltransferases.