A variation of a gene called CFH appears to increase the risk of developing Age-related macular degeneration, a potentially blinding deterioration of the retina, three groups of scientists report in the research journal Science.

Dr. Josephine Hoh, from Yale University School of Medicine in New Haven, Connecticut, and colleagues scanned the genomes of 96 people with Age-related macular degeneration (AMD)  and 50 unaffected people to look for genetic variations associated with the condition.

The researchers identified a common variant in the CFH gene that was strongly tied to AMD. As with most genes, people have two copies of CFH; when both copies of the gene were the variant type, the risk of having AMD was increased over sevenfold, the team found.

In a second study, Dr. Albert O. Edwards, from the University of Texas Southwestern Medical Center in Dallas, and colleagues identified the same genetic variant. They estimated that carriers had double to triple the risk of AMD, and that it accounted for 50 percent of cases of AMD.

In the third study, Dr. Margaret A. Pericak-Vance, from Duke University Medical Center in Durham, North Carolina, and colleagues also linked the same CFH variant with AMD. In their study, it increased the chances of developing AMD two to five times, and accounted for 43 percent of cases.

“Given the rapid aging of the population, an estimated 3 million individuals will have ... complications of AMD by 2020,” Dr. Edwards’ team points out. “Our findings suggest new avenues for developing preventative and therapeutic strategies for AMD,” they say.

SOURCE: Science, online March 10, 2005.