High APOE epsilon 4 allele frequencies associated with Alzheimer disease in a Tunisian population

Abstract

The goal of the study was to examine the Apolipoprotein E (APOE) genotypes in a Tunisian sample of patients with Alzheimer disease (AD) and normal controls, and to compare the results with the findings from the literature. A hospital-based case-control study of two groups (58 patients with AD, 71 controls) was conducted. Patients received a detailed clinical history, neurological examination, neuropsychological testing and brain imaging. A neurological examination and the Arabic version of the Mini-Mental State Examination were made for controls. Genotyping was performed using the PCR restriction fragment length polymorphism (PCR-RFLP) method. There were no statistical differences in age (p = 0.05) and gender (p = 0.046) between the two groups. The APOE ε4/4 genotype was over represented in the AD group in comparison with the controls (13.3 vs. 2.8%). A significant increased risk of AD among APOE ε4 allele carriers was observed. The odds ratio for the association of AD patients with homozygous and heterozygous ε4 allele was, respectively, 5.40 (1.35-21.48) and 2.90 (1.27-6.62). Our results in addition to previously published genetic studies suggest that AD disease is multifactor in origin. Ethnicity, genetic and environmental factors contribute to AD risk in different ethnic groups.