Nearly one in 2,000 people are at risk for inherited diseases of the retinadisorders that can claim their victims' vision. But such losses may one day be a thing of the past, thanks in part to findings described today in the journal Cell. According to the report, researchers have identified in mice a full set of vision genes, most of which have human counterparts.

Harvard Medical School geneticist Connie Cepko and colleagues found 300 genes expressed in photoreceptor neurons, the retinal cells commonly known as rods and cones. Only 36 of these genes were previously known. "This makes photoreceptors the single most well characterized cell type in the body," Cepko observes. The work should lead to the identification of those genes that, in their mutant forms, cause diseases like macular degeneration. And by getting a better sense of how these genes function, researchers might eventually be able to replace damaged cellsperhaps, Cepko muses, by manipulating the genes so as to coax replacement photoreceptors from stem cells. Indeed, "the more we know about how the genes work," she remarks, "the better we will be able to find ways to treat, and possibly, prevent disease."