A population-based study in Pima Indians suffering from T2DM has demonstrated that the 4G polymorphism in the promoter region of PAI-1 was associated with high risk of development of retinopathy, as elevated serum levels of PAI-1 result in dysfunctioning of the endothelium, which could lead to thickening of blood vessels [7]. The gene discussed is SERPINE1; the disease is type 2 diabetes mellitus.