Association of Apolipoprotein E (APOE) Gene Polymorphism With Age-Related Macular Degeneration (AMD) in Indian Patients

TL;DR

This study examines the link between APOE gene variations and age-related macular degeneration in Indian patients, finding limited association but suggesting a possible role for the E4 allele.

Contribution

The study provides population-specific insights into APOE and AMD in Indian patients, highlighting potential ethnic differences.

Findings

The E3/E3 genotype was most common in both AMD patients and controls.

The E2/E2 genotype showed a protective effect against AMD.

The E4 allele was more frequent in AMD cases but did not reach significant association.

Abstract

Background

Age-related macular degeneration (AMD or ARMD; Online Mendelian Inheritance in Man (OMIM) #603075) is the degenerative disease of the retina that causes progressive impairment of central vision, leading to irreparable vision loss in older persons.

Objective

The objective was to investigate the association between apolipoprotein E (APOE) gene polymorphism and AMD in Indian patients.

Materials and methods

Genotyping for APOEvariants was performed in 121 AMD patients and 100 healthy controls using a polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method, followed by sequencing. Genotype and allele were analyzed using the allele counting method. P-value < 0.05 was considered statistically significant.

Results

The E3/E3 genotype has a frequency of 76/100 (76%) in controls and 97 (80%) in AMD. The frequency of the heterozygous E2/E2 genotype was 19 (19%) in controls and eight (6.6%) in AMD, and the variant E4/E4 genotype was found in one control (1%) and in one AMD case (1%). Some protective effect of the E2/E2 heterozygous genotype is seen (OR = 0.30; P-value = 0.009). Wild allele E3 in controls was 155 (77.5%) in AMD 209 (86.3%), E2 allele 41 (20.5%), and 17 (7%) in controls and AMD. E4 alleles in controls were four (2%) and 16 (6.6%) in AMD. E2 allele showed a protective effect; we did not find any significant association in APOE variant genotypes, and the odds ratios were within a 95% confidence interval (95% CI). As independent risk factors for AMD, logistic regression (LR) analysis was applied using E2, E3, and E4 alleles and their genotypes.

Conclusion

This study raises the possibility that the APOE gene might not have a significant association with AMD in Indian patients. However, our sample statistics suggest that the APOE E4 allele may be a risk factor for AMD in the Indian population. The study requires verification in a large sample size, across different parts of the country, and among other ethnic groups.

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