U.S. scientists say multiple genetic variants together explain a high proportion of inherited risk of age-related macular degeneration.

AMD is a degenerative disorder of the eye affecting the central retina and is one of the most common causes of vision loss in the elderly. The risk of developing AMD is influenced by genetic and environmental components.

Previous studies showed a common variant form of a protein called complement factor H, or CFH, is associated with increased AMD susceptibility. Two studies show additional variants within the CFH gene, which do not affect the function of the protein, also make an important contribution to disease risk.

In one study, Gonçalo Abecasis and colleagues at the University of Michigan examined variants within and surrounding the CFH gene and found, among other things, variants in the gene encoding CFH, which do not change the protein itself, strongly contribute to the risk of AMD.

In another study, Mark Daly and colleagues at the Massachusetts General Hospital examined an independent set of AMD cases and similarly found a common non-protein-coding variant in CFH influences disease risk.

Both studies are detailed in the September issue of the journal Nature Genetics.

Source: United Press International