Clinical and neuropsychological profile of Alzheimer's disease in Tunisia and the impact of APOE gene.

Authors

Alya Gharbi, Ikram Sghaier, Mohamed El Habibi, Youssef Abida, Amira Souissi, Amal Atrous, Meriem Zantour, Imen Kacem, Amina Gargouri Berrechid, Mouna Ben Djebara, Riadh Gouider

Published in

Frontiers in genetics. Volume 17. Pages 1831886. Epub Jul 01, 2026.

Abstract

Alzheimer's disease (AD), the leading cause of major neurocognitive disorder (MNCD) worldwide and in Tunisia, is strongly associated with Apolipoprotein E (APOE). In the present study our aims are to characterize the clinical profile of Tunisian patients, determine APOE allelic and genotypic frequencies, and asses their influence on disease phenotype.
We included patients with a clinical diagnosis of probable or possible AD, who consulted in the Department of Neurology at Razi University Hospital over a span of 21 years. Demographic, clinical, and neuropsychological data were assessed. APOE genotyping was performed and its correlation to AD clinical features was evaluated.
Among 1,010 AD patients, the sex ratio was 0.62, with a mean age at onset of 68.9 ± 9.8 years. Consanguinity was reported in 30.2% of cases, and a family history of major neurocognitive disorder in 65.3%. The mean Mini-Mental State Examination (MMSE) and Frontal Assessment Battery (FAB) scores were 14.1 ± 7.7 and 6.5 ± 4.8, respectively. Overall, 47.0% of patients carried the APOE ε4 allele. The APOE ε3/ε3 genotype was the most frequent (45.94%), followed by APOE ε3/ε4 (40.99%). Age at onset was significantly earlier in APOE ε4 carriers compared to non-carriers (68.17 ± 10.05 vs. 69.53 ± 9.61 years; p = 0.027). Baseline cognitive performance was also significantly lower in APOE ε4 carriers, with reduced MMSE (11.65 ± 6.77 vs. 16.40 ± 7.85; p < 0.001) and FAB scores (5.46 ± 4.09 vs. 7.35 ± 5.11; p < 0.001). Neuropsychiatric assessment revealed significant associations between APOE ε4 carriage and visual hallucinations (p = 0.0015), aggressivity (p = 0.0022), disinhibition (p = 0.0039), and aberrant motor behavior (p = 0.0054). Finally, stratified analysis of the AD cohort according to educational attainment and APOE risk allele status demonstrated distinct patterns of cognitive impairment across the different subgroups.
The APOE ε4 allele, frequent in North African AD, appears to function not only as a genetic risk factor for AD, but also as a potential indicator, influencing disease onset and clinical severity.

PMID:
42460155
Bibliographic data and abstract were imported from PubMed on 16 Jul 2026.

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