Apolipoprotein E polymorphism carriers exhibit objective cognitive deficits: a single center trial

Objective To assess the correlation between objectively measured cognitive function and apolipoprotein E polymorphism within one geographic region. Methods 61 patients, aged 55-90 years old, were enrolled in a memory clinic at the Beijing Luhe Hospital affiliated with Capital Medical University from September 2016 to September 2018. At this center, they were evaluated with neuropsychological scales to assess their memory and other aspects of cognitive function. Specific gene segments were extracted from venous blood by PCR amplification, and ApoE genotyping was carried out by chip hybridization. Results Among all patients, 0 had the genotype epsilon 2/2, 7 had the genotype epsilon 2/3, 0 had the genotype epsilon 2/4, 40 had the genotype epsilon 3/3, 12 had the genotype epsilon 3/4, and 2 had the genotype epsilon 4/4. The allele frequency epsilon 2 accounted for 5.74%, epsilon 3 accounted for 81.15% and epsilon 4 accounted for 13.11%. The Mini-Mental State Examination (MMSE) scores of epsilon 4 carriers (18.14 +/- 0.39) were significantly lower than those of non-epsilon 4 carriers (23.77 +/- 6.29) (P < 0.05), and the Montreal Cognitive Assessment (MoCA) scores of epsilon 4 carriers (14.36 +/- 7.56) were also significantly lower than those of non-epsilon 4 carriers (20.55 +/- 8.08) (P < 0.05). Conclusion The rate of the epsilon 3/3 homozygous genotype was the highest, followed by the rates of the epsilon 3/4 and epsilon 2/3 genotypes. The rates of the epsilon 2/4, epsilon 4/4, and epsilon 2/2 genotypes were the lowest. Deficits in memory and other cognitive processes were significantly more pronounced in epsilon 4 carriers than in non-epsilon 4 carriers.