Three genes associated with age-related macular degeneration have been identified by U. S. researchers.

Age-related macular degeneration is a leading cause of visual impairment and blindness in older adults, study leader Anand Swaroop of the National Eye Institute, part of the National Institutes of Health, and the University of Michigan in Ann Arbor said.

The strongest age-related macular degeneration genetic association was found on chromosome 22, near a gene called metalloproteinase inhibitor 3 (TIMP3), Swaroop said.

Dr. Paul A. Sieving, director of the National Eye Institute, said in a statement, "Genome-wide association studies require large numbers of patients to discover significant genetic associations. The success of this effort was made possible by a community-wide scientific collaboration of sharing DNA samples and analyzing the genomes of more than 18,000 people. This study increases our understanding of DNA variations that predict individual risks of and provides clues for developing effective therapies."

Proceedings of the National Academy of Sciences have published the findings. (With Inputs from Agencies)