Role of ENPP1 Gene Variants in the Susceptibility to Diabetic Nephropathy in Patients with type 2 Diabetes Mellitus

Genetic factors are known to play a significant role in the susceptibility of diabetic patients to severe complications such as diabetic nephropathy (DN). This study aimed to evaluate the association between polymorphism of ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) variants (rs997509, K121Q, rs1799774, and rs7754561) and DN in patients with type 2 diabetes mellitus (T2DM). A total number of 492 patients with T2DM with and without DN were categorized into case and control groups. The extracted DNA samples were genotyped using TaqMan allelic discrimination assay amplified by polymerase chain reaction (PCR). The haplotype analysis among the case and control groups was performed using an expectation-maximization algorithm by the maximum-likelihood method. The analysis of laboratory findings demonstrated significant differences in fasting blood sugar (FBS) and hemoglobin A1c (HbA1c) between the case and control groups (P < 0.05). The results showed that K121Q was significantly related to DN under a recessive model of inheritance (P = 0.006); however, rs1799774 and rs7754561 both were protective for DN under a dominant model of inheritance (P = 0.034 and P = 0.010, respectively) among four studied variants. Two haplotypes, including C-C-delT-G with a frequency < 0.02 and T-A-delT-G with a frequency < 0.01, were associated with the increased risk of DN (P < 0.05). The present study demonstrated that K121Q was associated with the susceptibility of DN; however, rs1799774 and rs7754561 were protecrtive variants for DN in patients with T2DM.