Association Between DPP-4 Gene Polymorphism And Serum Lipid Levels In Chinese Type 2 Diabetes Individuals

OBJECTIVEDPP-4 was verified as being associated with dyslipidemia, the major driver of cardiovascular diseases in type 2 diabetes. We detected four variants of the DPP-4 gene in type 2 diabetes and tested for an association with dyslipidemia.METHODSA total of 190 patients of Han nationality in Shandong Province, China, who were diagnosed with type 2 diabetes and aged between 18 and 75 were genotyped from July 2012 to June 2014. Four single-nucleotide polymorphisms (SNPs) of DPP-4 were selected, including rs4664443 (C/T), rs7608798 (T/C), rs1558957 (C/T) and rs3788979 (A/G). And analyzed whether they were in strong linkage disequilibrium. Because plasma lipid levels tend to be affected by diet, drug therapy and morbid state, we reviewed the medical records of all 190 individuals, and selected 82 participants for analysis. Physiological and biochemical parameters for each patient, including gender, age, height, weight, body mass index (BMI), mean glycosylated hemoglobin (HbA1c), fasting plasma glucose (FPG), serum triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (ApoB) levels were collected. A one-way analysis of variance (ANOVA) and a multiple genetic factor analysis was used to analyze the trends in lipid covariates across the genotypes.RESULTSThe genetic polymorphism of rs4664443, rs3788979, rs7608798 and rsl558957 in the 190 Chinese type 2 diabetes individuals were consistent with Hardy-Weinberg equilibrium (χ2=0.20, P=0.65 for rs4664443;χ2=0.034,P=0.85 for rs1558957; χ2=1.37, P=0.24 for rs7608798; χ2=1.04, P=0.31 for rs3788979), and they were not in strong linkage disequilibrium with each other (r<0.7). Among the selected 82 individuals, carriers of the minor allele T were at higher risk of having high serum TG (P=0.013), LDL (P=0.044) and ApoB (P=0.006) levels in rs4664443. And serum TG level was different between CC and CT type in rsl558957 (P=0.077). Homozygote TT of rs7608798 was at a lower risk to have elevated serum TG level (P=0.037). In rs3788979, the serum TG level and BMI among genotypes of AA, AG and GG were significantly different (P=0.034, P=0.04, respectively). We defined the unfavorable allele of the four variants and observed that individuals with more than two unfavorable alleles were most likely to have a higher level of TG (P=0.004), TC (P=0.011), and BMI (P=0.044).CONCLUSIONSThis is the first study to investigate DPP-4 allelic distributions and their association with dyslipidemia in Chinese type 2 diabetes patients, which may have clinical significance.