Seven Genetic Risk Factors Associated with Age-related Macular Degeneration

Seven new regions of the human genome are now associated with an increased risk of age-related macular degeneration, a leading cause of blindness among older adults. 

According to recent reports from Case Western University School of Medicine, a study is working to help identify the causes and concerns associated with these risks. 

The AMD Gene Consortium, a network of international investigators representing 18 research groups, has also confirmed the existence of 12 other regions -called loci-that had been identified in previous studies. The reported findings can be found in the journal Nature Genetics.

Supported by the National Eye Institute (NEI), a part of the National Institutes of Health, the study represents the most comprehensive genome-wide analysis of genetic variations associated with AMD.

"This work represents a big step forward toward solving why some people get AMD, while others do not," said Sudha Iyengar, PhD, professor of epidemiology and biostatistics at Case Western Reserve School of Medicine and a member of the consortium's senior executive committee.

"This disease is not caused by a single change in the DNA, but represents many events that accumulate over the lifetime of a patient. Identification of these genes provides molecular windows into the AMD disease process."

According to reports, AMD affects the macula, a region of the retina responsible for central vision. The retina is the layer of light-sensitive tissue in the back of the eye that houses rod and cone photoreceptor cells. Compared with the rest of the retina, the macula is especially dense with cone photoreceptors; humans rely on the macula for tasks that require sharp vision, such as reading, driving, and recognizing faces. As AMD progresses, such tasks become more difficult and eventually impossible. Some kinds of AMD are treatable, but no cure exists, and an estimated 2 million Americans suffer from AMD.

The consortium's analysis included data from more than 17,100 people with the most advanced and severe forms of AMD, which were compared to data from more than 60,000 people without AMD. The 19 loci that were found to be associated with AMD implicate a variety of biological functions, including regulation of the immune system, maintenance of cellular structure, growth and permeability of blood vessels, lipid metabolism, and atherosclerosis.