Genetics and Age-related Macular Degeneration

Written by John Yeo
Posted on December 24, 2018

What is Age-related Macular Degeneration (AMD)?

Age-related macular degeneration (AMD) is an acquired disease of the macula characterized by progressive visual impairment because of late-onset neurodegeneration of the photoreceptor-retinal pigment epithelial complex.

AMD is a disease of the retina which accounts for 8.7% of blindness worldwide and is the leading cause of visual impairment in developed countries particularly in people older than 60 years old.

Its prevalence is likely to increase as a consequence of exponential population aging.

Major risk factors leading to AMD include cigarette smoking, nutritional factors, cardiovascular diseases, sunlight exposure, a low-antioxidant diet, and genetic markers, including genes regulating complement, lipid, angiogenesis, and extracellular matrix pathways.

How does this affect you?

Figure 1: Image modified from National Eye Institute, National Institutes of Health

AMD causes damage to the macula, a small spot near the center of the retina and the part of the eye needed for sharp, central vision, which lets us see objects that are straight ahead.

This is necessary for recognising faces, reading books or using mobile screens, watching television, sewing, preparing food, driving, safely navigating stairs and performing other daily tasks we take for granted.

AMD can be classified as either early-stage or late-stage. In the early-stage, the visual function of patient is good. The early stages of AMD may progress to late stage of AMD, either atrophic (‘dry’) or exudative (‘wet’) AMD. It will cause vision loss once it progresses to late stage of AMD.

Genetics and AMD

Significant progress has been made in the discovering and deciphering AMD over the past 20 years. The significant discovery is the disease-susceptive single nucleotide polymorphism (SNPs) of AMD.

The development of AMD is associated with at least 15 genes with a substantial number of SNPs involved. Among them, CFH (complement factor H) gene Y402H polymorphism, 162V polymorphism, HTRA1 (high temperature requirement A-1) promoter and ARMS2 (age-related maculopathy susceptibility-2) gene A695 polymorphism are the most important SNPs so far discovered.

What can you do about it?

Diet

  • Higher dietary intakes of carotenoids
  • Reduce total fat intake
  • Increase consumption of omega-3 fats

Lifestyle

  • Avoid smoking
  • Reduce weight to normal weight
  • Do more physical activity
  • Regular intake of antioxidant multivitamin and mineral supplementation

References:

1. Nowak, J. Z. (2006). Age-related macular degeneration (AMD): pathogenesis and therapy. Pharmacological Reports, 58(3), 353.

2. Yoshimura, N. (2010). Age‐related macular degeneration and genetics. Clinical & experimental ophthalmology, 38(1), 1-1.

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