For example, elevated albuminuria correlated with hypomethylation of tissue inhibitor metalloproteinase-2 (TIMP-2) and aldo-keto reductase family 1 member B [302], while higher serum homocysteine levels were observed in DKD patients with increased promoter methylation of the methylenetetrahydrofolate reductase gene [303]. This evidence concerns the gene TIMP2 and diabetic kidney disease.