Although the genetic mutations discovered by the researchers affect only about two percent of patients with the disorder, the findings offer important insights for researchers who seek to understand age-related macular degeneration (AMD).

"The clinical entity that we call AMD is actually as many as fifty diseases," said the study's lead author, HHMI investigator Edwin M. Stone, who is at the University of Iowa Carver College of Medicine. "They simply look so similar that clinicians call them the same thing. Because of such complexity, we don't understand the molecular mechanisms of the disease very well, and this has limited our ability to develop preventive therapy for it.

"Looking for genetic causes of AMD is potentially very meaningful because it will help us identify the mechanisms of the disease," he said. "Knowing the genetic bases of AMD would also enable us to create an animal model that could be used to test therapies. And, if we understood several of the mechanisms, we could potentially divide the patient population into clinically relevant subgroups, so that we could direct specific treatments to those most likely to benefit from them."

Stone and HHMI investigator Val C. Sheffield led the research team that published its findings in the July 22, 2004, issue of the New England Journal of Medicine (NEJM). Stone and Sheffield collaborated on the study with colleagues at the University of Iowa and the University of Southampton.

AMD is a worldwide problem, affecting some seven million people in the United States alone. Vision loss occurs when depo
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Contact: Jim Keeley
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
21-Jul-2004