APOE genetic variability in an Egyptian cohort of PD

Eman M Khedr¹Martina B William²Aliaa El-Hosseiny²Ali Soliman Shalash³Gharib Fawi⁴Mohamed H. Yousef²Shaimaa Ibrahim El-Jaafary⁵Hamin Lee⁶Alina Jama⁶Mohamed Koraym¹Asmaa Helmy³Yara Salah³David Adel³Nourelhoda A Haridy¹Samir Nabhan²Agsha Atputhavadivel⁶Sara Elfarrash⁷Gaafar Ragab⁵Mohamed Tharwat Hegazy⁵Yasmin Elsaid⁷Asmaa S Gabr²Nourhan Shebl²Lobna Ahmed Mohamed⁸Nesreen Abdelwahhab⁷Tamer M Belal⁷Nehal A B Elsayed⁹Mohamed Elgamal⁷Shimaa Elgamal¹⁰Salma Ragab¹⁰Jaidaa Mekky⁸Henry Houlden⁶Mie Rizig⁶Mohamed Mosaad Salama^2*

• ¹Assiut University, Assiut, Asyut, Egypt
• ²American University in Cairo, Cairo, Egypt
• ³Ain Shams University, Cairo, Cairo, Egypt
• ⁴Sohag University, Sohag, Egypt
• ⁵Cairo University, Giza, Giza, Egypt
• ⁶University College London, London, England, United Kingdom
• ⁷Mansoura University, Mansoura, Dakahlia, Egypt
• ⁸Alexandria University, Alexandria, Alexandria, Egypt
• ⁹Mansoura International Hospital, Mansoura, Egypt
• ¹⁰Faculty of Medicine, Kafrelsheikh University, Kafrelsheikh, Egypt

Background: The apolipoprotein E (APOE) gene, encompassing three alleles (ε2, ε3, ε4), is a critical player in lipid metabolism and has been extensively studied for its role in neurodegenerative diseases. This study examines APOE genetic variability and its association with PD in an Egyptian cohort. Methods: A total of 891 participants, including 422 PD patients and 469 healthy controls, were included in this study. APOE genotyping was performed using Kompetitive Allele Specific PCR (KASP) to detect the rs429358 and rs7412 SNPs, which define the APOE alleles. APOE alleles were categorized based on the genotypes into ε2, ε3, and ε4 groups. Clinical assessments of PD patients included age at onset, disease severity (MDS-UPDRS), and demographic factors. Statistical analyses compared APOE distributions between PD and control groups and examined associations with clinical variables. Results: The ε3 allele was the most prevalent in the cohort (77.3%), aligning with global and African trends. The ε2 allele was observed in 11.4%, and the ε4 allele in 11.3%, with both frequencies being lower than reported African estimates. The ε3/ε3 genotype was predominant in both PD patients (72.51%) and controls (72.07%). The ε4/ε4 genotype was absent in PD cases and rare among controls (0.64%). No significant association was found between APOE genotypes and PD risk, age at onset, or disease severity. Conclusion: Our findings do not support a significant role for APOE in PD susceptibility or severity in Egyptians.