Researchers from Columbia and IowaUniversities have uncovered new information about a gene responsible for the most common cause of blindness in the elderly, a scientific journal reported Monday.

Studies about the gene, called Factor H, are helping biotech companies to find treatments for age-related macular degeneration (AMD). Scientists now believe the gene is triggered by a bacterial or viral infection, according to the article in the Proceedings of the National Academy of Sciences.

AMD is an extremely common disease in the baby boom generation, and therefore a very lucrative potential market for biotech companies. As much as 30 percent of the global population will have some form of AMD by the time they reach the age of 75.

The disease is currently the most common cause of blindness in those over 60, and more than 50 million people worldwide are irreversibly blind because of it. The Toronto, Canada-based AMD Alliance International says there are 13 million sufferers in the United States alone.

“As our research progresses, we should eventually be in a position to suggest treatment that could keep many people from going blind,” said Dr. Gregory Hageman, professor of ophthalmology and visual sciences at the University of Iowa.

People who suffer from AMD progressively loose the ability to see straight in front of them as a special region of the retina degenerates.

The study is one of four that have been published recently about the genetics behind the disease. Research papers from three independent teams appeared in the April 15 issue of Science, all indicating that Factor H is the important gene behind the disease.

“They confirm a strong genetic component of AMD, which may allow scientists to develop tests for the disease before symptoms begin to appear and when therapies might help slow its progress,” said Dr. Paul A. Sieving, director of the National Eye Institute.

However, this piece of research is the first to examine the role of the body’s immune response in causing AMD and is likely to provide new avenues for the research and development of drugs, according to the researchers.

Several biotech companies are currently working on treatments for AMD using a technique called RNA interference (RNAi), which essentially turns down the effects of disease-related genes.

Analysts said biotech companies like Sirna Therapeutics of Boulder, Colorado, and Cambridge, Massachusetts-based Alnylam Pharmaceuticals could see their first therapeutic sales as early as 2008. By that time, sales are expected to total $300 million (see Top 10 Trends: Silencing the Genes).