Association Between 3'APOB-VNTR Polymorphism and Plasma Lipid Profiles in Type 2 Diabetes Patients

Apolipoprotein B (APOB) plays an important role in the metabolism of cholesterol and impairment in its function can lead to cholesterol accumulation in the pancreatic islets. It can then reduce insulin secretion and lead to Type 2 diabetes (T2DM). The purpose of this study was to investigate the association of 3chr('39')APOB-VNTR polymorphism with plasma lipid profiles in T2DM individuals in Khorasan Razavi province, Iran.

In this case-control study, 204 patients with T2DM and 207 non-diabetic volunteers were examined as a control group. All samples were analyzed for plasma lipid profiles. Genotypes were determined by PCR and electrophoresis. Differences in lipid variables between genotypes were assessed using one-way analysis of variance (ANOVA) with SPSS 20.0.

We found 18 different alleles of the APOB gene 3chr('39')VNTR comprising from 26 to 45 hypervariable elements (HVEs) in the control groups and 21 alleles ranging from 30 to 51 repeats in the T2DM patients. Short alleles (26 to 29 HVEs) were only in controls and large alleles (46 to 51 HVEs) were only in T2DM patients. Our results showed that in people with long HVE polymorphism, HDL-C levels decreased, but LDL-C increased. Therefore, longer alleles for T2DM are considered risk factors. It was also observed that the TC / HDL-C ratio was significantly lower in shorter genotypes than the longer genotypes in T2DM patients.

It is concluded that 3chr('39')APOB-VNTR polymorphisms, especially longer alleles, affect plasma lipid levels in individuals with T2DM and are risk factors for this disease.