More genetic studies shed light on AMD

Three studies conducted independently of one another have linked a single gene variation to an increased risk for development of age-related macular degeneration. A separate study in twins has also shown the influence of genetics on the disease.

The three studies, reported earlier this month in the journal Science, found that a single nucleotide polymorphism of the complement factor H gene increases the risk of development of AMD by at least threefold, according to press releases from institutions involved in the studies.

This single genetic variation may be responsible for up to 50% of all AMD cases, according to researchers at University of Texas Southwestern Medical Center.

The gene variant alters a protein that is normally involved in the body’s immune system, according to a researcher at Rockefeller University. Variations like this one can change a gene’s protein products in a way that may increase susceptibility to a disease such as AMD, a press release from Rockefeller said.

Researchers are hopeful that the identification of this risk factor for AMD could lead to the development of diagnostic tools for the disease. The three studies were conducted by researchers at the University of Texas Southwestern in Dallas, Boston University and Sequenom, a biotech firm; Duke and Vanderbilt Universities; and Rockefeller and Yale Universities and the National Eye Institute.

An unrelated report released Monday linked AMD with genetics through a study of 840 sets of twins. The study found that identical twins with AMD were twice as likely as fraternal twins to have similar levels of blindness. This study, by Johanna M. Seddon, MD, ScM, and colleagues at Harvard, is published in the current issue of Archives of Ophthalmology.