Vision loss

Gene variants linked to progression of eye disease

People with variations in two common genes are two to four times at higher risk of developing advanced age-related macular degeneration (AMD), the most common cause of vision loss in people over age 60, according to a new Tufts study. And when combined with smoking and obesity—already-known risk factors for advanced AMD—the genetic variations push the risk of advanced AMD 19 times higher.

People with advanced AMD lose so much of their central vision that they can no longer drive or read.

“Genetic factors, smoking and obesity are all independent factors related to progression of AMD, and they seem to be additive,” said lead researcher Johanna M. Seddon, director of the Ophthalmic, Epidemiology and Genetics Service at Tufts-New England Medical Center and the New England Eye Center and an instructor in ophthalmology at the School of Medicine. Seddon and her colleagues studied almost 1,500 white adults, ages 55 to 80, with intermediate signs of macular degeneration. During an average of more than six years of follow-up, 281 individuals progressed to advanced AMD in one or both eyes.

But Seddon and her co-authors, who include Sarah George and Bernard Rosner of Harvard, say it’s too early to call for genetic screening. Many, but not all, people with the gene variations progress to advanced AMD, but so do some people without the variation.

The study was funded by the National Eye Institute and other grants and was published in the Journal of the American Medical Association.

This story appeared in the July issue of the Tufts Journal.