By Adrian Galbreth
As one of the leading causes of sight loss around the world, particularly in developed countries, age-related macular degeneration (AMD) has been the subject of much scientific study as experts attempt to develop new ways of treating or identifying the condition.
Although there is currently no known treatment or cure or for the vast majority of AMD patients, a new study carried out by experts at the University of California Santa Barbara, the University of Utah John Moran Eye Center, and the University of Iowa suggests a new way of identifying sufferers.
The research, published in BioMed Central's open access journal Genome Medicine, identifies genes whose expression levels can identify people with AMD, as well as distinguishing between AMD subtypes.
Previous genome-wide research has indicated that genes involved in the innate immune system and fat metabolism are involved in this disease, although none of the studies examined gene expression differences between AMD and normal eyes.
In the new study, the experts used a human donor eye repository to identify genes up-regulated in AMD, with the ability of these genes to recognise AMD tested on a separate set of samples.
They found that over 50 genes had higher than normal levels in AMD, with the top 20 of able to 'predict' a clinical AMD diagnosis.
The genes over-expressed in the RPE-choroid included components of inflammatory responses, while in the retina, the researchers found genes involved in wound healing and the complement cascade, which is a part of the innate immune system.
They also found retinal genes with expression levels that matched the disease severity for advanced stages of AMD.
Not only are these genes able to identify people with clinically recognised AMD and distinguish between different advanced types, but some of the genes appear to be associated with pre-clinical stages of AMD, said Dr Monte Radeke, one of the project leaders.
"This suggests that they may be involved in key processes that drive the disease. Now that we know the identity and function of many of the genes involved in the disease, we can start to look among them to develop new diagnostic methods, and for new targets for the development of treatments for all forms of AMD," the expert added.
by Alexa Kaczka