Apolipoprotein E polymorphisms in adults over 60 years of age with mild cognitive impairment and Alzheimer’s disease in different Venezuelan populations

Introduction: Alzheimer’s disease represents a serious public health problem that tends to worsen over time. Among the most important genetic predisposing factors is the presence of the ε4 allele of the apoprotein E gene (APOE). Objective: To determine the allelic and genotypic frequencies of the APOE isoforms in adults over 60 years old with mild cognitive impairment and Alzheimer’s disease in Gran Caracas and in the indigenous Pemón community of the Kamarata-Kanaimö area, Bolívar State. Materials and methods: We studied 267 patients: 96 controls, 40 with mild cognitive impairment, 108 with Alzheimer’s from Caracas, and 23 individuals from Kamarata-Kanaimö. The APOE isoforms were determined with the AP1210Z: Seeplex® ApoE Genotyping kit. Results: The allele ε4 showed a significant association with mild cognitive impairment (OR=5.03; 95% CI: 0.98-25.70) and EA (OR=5.78; 95% CI: 1.24-26.85). The genotype frequencies for the control and mild cognitive impairment groups were ε3/ε3> ε3/ε4> ε2/ε4> ε3/ε2> ε4/ε4, and for the Alzheimer’s group, ε3/ε3> ε3/ε4> ε4/ε4> ε2/ε4> ε3/ε2 In Kamarata-Kanaimö, the order was ε3/ε3> ε3/ε4> ε4/ε4; the allele ε2 was not found in this group. Conclusions: APOE allelic and genotypic frequencies in our sample showed a similar distribution to those found in other studies in Venezuela and the Americas. The absence of the ε2 allele in the indigenous community of Kamarata-Kanaimö warrants further investigation. The positive association of the ε4 allele with both Alzheimer’s and mild cognitive impairment was reinforced. The early determination of the ε4 allele carriers can help establish preventive measures in our population.