New research led by New York's Columbia University suggests that almost three-quarters of the cases of age-related macular degeneration (AMD) are linked to two genes. AMD happens to be one of the leading causes of blindness in the world.
"I am not aware of any other complex disorder where nearly 75% of genetic causality has been identified," said lead researcher Dr Rando Allikmets. "These findings are significant because they absolutely confirm the roles of these two genes and, consequently,
the central role of a specific immune response pathway, in the development of AMD." AMD is caused due to the degeneration of an area called macula. This area is located in the retina and is responsible for maintaining fine, central vision. Earlier studies had pointed out a gene called Factor H as being the culprit in this condition. This gene is known to stop the body's immune response once infection is brought under control. However an alteration in Factor H might trigger AMD in later life. The current study analyzed 1,300 people and discovered that a second factor named Factor B also plays a vital role in this. While H is responsible for shutting down immune response, B plays a role in triggering it. In the current study, researchers found that 74 percent of MAD patients had alterations of either of these genes, "In just a few short years, we've gone from knowing very little about what causes AMD to knowing quite a lot. We now have clear targets for early therapeutic intervention," Allikmets commented. The details of the study appear in the journal Nature Genetics.