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.

Angiotensin-converting enzyme (ACE) has shown altered activity in patients with neurological diseases. An insertion/deletion (I/D) polymorphism of the ACE gene encoding angiotensin-converting enzyme has been reported to be associated with the risk for Alzheimer's disease (AD), and is generally considered to be a disorder primarily affecting memory. We conducted a case-control study in a sample composed of 85 sporadic AD patients and 90 age- and sex-matched controls to investigate the possible effect of the polymorphism and cognitive profile. Our data revealed an association between the ACE polymorphism and AD risk. There was a significant difference in the ACE allele or genotype frequencies between cases and controls. The D/D genotype showed an increased risk for AD and in the amnestic group and the effect was independent on ApoE genotypes.

The apolipoprotein E (APOE) is a well-established risk factor for late-onset Alzheimer's disease (AD). Several studies have attempted to confirm the association between the polymorphism located at position -491 in the transcriptional regulatory region of the APOE gene and AD. We examined in 85 AD patients and 90 control subjects of a Tunisian population the potential involvement of this polymorphism as a risk factor for AD, either through an independent effect or through interaction with the existing APOE ε4 allele risk. The T allele frequency was significantly higher in the AD patients group (45.3 %) than in the controls group (32.78 %) and may possibly constitute a significant risk factor for AD. The APOE ε4 allele did not influence the distribution of the -491 polymorphism after stratification.

No abstract