Association of APOE Gene Polymorphism with Alzheimer's Disease and the Impact of Age, Gender, and Type 2 Diabetes Mellitus in Iraqi Patients

The present study aimed to explore the linkage of APOE gene polymorphism with AD and to assess the effects of age, gender and type 2 Diabetes mellitus (T2DM) in Iraqi population. The study included 62 patients with AD and 48 control patients. In clinical results, the incidence of AD was observed to be higher in women than in men, higher with age, and T2DM was shown to be a significant factor in the progression of the disease.The molecular analysis was performed using Real-Time PCR for the APOE polymorphism (rs429358) and two alleles (T and C) and three genotypes (TT, TC and CC) were found within the study groups. The frequencies of the genotypes were TT (OR=0.46, 95% CI=0.25-0.91), TC (0.274) and CC (0.177) in the AD patients. Regarding allelic frequencies, the T allele frequency was 0.66 (OR=0.628, 95% CI=0.59–1.01), whereas the C allele frequency was 0.33 (OR=1.89, 95% CI=1.6–4.26). Based on these results, it can be concluded that the analyzed population is highly susceptible to AD because the APOE gene variants play an important role, in addition to other metabolic and demographic factors.