Association of APOE Serum Levels and APOE ε2, ε3, and ε4 Alleles with Optic Neuritis

Abstract
Optical neuritis (ON), otherwise known as optical nerve damage, is a term used to describe various environmental and body conditions that lead to optic nerve dysfunction. Neurologists are well aware of conditions that cause optic neuropathy, such as trauma, infections, malnutrition, and various toxins. As optic neuritis is a multifactorial demyelinating or infectious process, genetic predisposition may also influence the progression of optic neuritis. This study aimed to evaluate the association of ON (with and without multiple sclerosis) with APOE alleles and APOE serum levels. We found that the APOE ε3/ε3 genotype was statistically less common in the ON group of males than in the control group (p = 0.045). Moreover, the APOE ε3/ε3 genotype had a 3.7-fold increase in the odds of ON development in males (OR = 3.698; CI: 1.503–9.095; p = 0.004). In contrast, the APOE ε3/ε4 genotype had a 4.1-fold decrease in the odds of ON development in males (OR = 0.242; CI: 0.083–0.704; p = 0.009). APOE serum levels were statistically significantly higher in the ON group than in the control group (p = 0.042). The APOE ε3/ε3 genotype may increase males’ risk of developing ON, while the ε3/ε4 genotype may reduce males’ risk of developing ON.