Genes linked to blindness in elderly

A new study suggests that nearly two- thirds of patients with age-related macular degeneration (AMD) carry variants in one or both of the Factor H and Factor B genes. About 74 percent of AMD patients carry certain variants in one or both genes that significantly increase their risk of developing this disease.

Researchers at Columbia University Medical Center pinpointed the role that two genes Factor H and Factor B play in the development of nearly three out of four cases of age-related macular degeneration, a devastating eye disease that affects more than 10 million people in the US.

The study published in Nature Genetics, led by Rando Allikmets, showed that several variants in the Factor H gene significantly increase the risk of developing age-related macular degeneration.

The PNAS study found that several variants in the Factor H gene significantly increase the risk of developing AMD. Researchers decided to search for additional culprits and focused on genes in the same immune response pathway that contains Factor H.

They performed genetic analysis of 1,300 people and identified Factor B as the major modifier of the disease.

While Factor H inhibits the immune response to infection, Factor B is an activator.

« 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. We confirmed this association not just statistically and genetically but, most importantly, pinpointed the biological origin of the disease, » said Dr. Allikmets. « We confirmed this association not just statistically and genetically but, most importantly, pinpointed the biological origin of the disease… 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. »

Factor H encodes a protein that helps shut down an immune response against bacterial or viral infection, once the infection is eliminated. People with these inherited risk-increasing variations of Factor H are less able to control inflammation caused by infectious triggers, which may spark age-related macular degeneration later in life.