(Salt Lake City, Utah) --A variant in a gene called Complement Factor H (CFH) appears to contribute to the increased risk of advanced age-related macular degeneration largely or entirely through its impact on the development of soft drusen as a precursor of advanced age-related macular degeneration (AMD), according to researchers from the University of Utahs John A. Moran Eye Center. Several research groups recently showed that CFH increases the risk for advanced AMD. However until this study, its impact on soft drusen and advanced AMDor the relationship between themwas unclear.
In an article to be published online in November 29 and in print in January by Public Library of Science Medicine, researchers say that CFH is a major risk factor for soft drusen, which are small yellowish, extracellular deposits of lipid, protein and cellular debris in the macula. Soft drusen are considered the precursor of advanced age-related macular degeneration. They are found in about half of early age-related macular degeneration cases and are a risk for advanced age-related macular degeneration.
While the CFH variant is a risk factor for soft drusen, not all individuals with soft drusen will develop macular degeneration with vision loss, said Kang Zhang, M.D., Ph.D. of the John A. Moran Eye Center at the University of Utah, one of senior authors on the paper who led the University of Utah team. The work involved researchers in the Department of Ophthalmology and Visual Sciences, in the Program in Human Molecular Biology and Genetics at the Eccles Institute of Human Genetics. It is likely that there are other important genes yet to be found that contribute to the risk of age-related macular degeneration, especially among those who already have soft drusen.
"Most patients with soft drusen are without any visual symptoms for decades and only a fraction of individuals who have soft drusen will eventually progress to advanced age-related macular degeneration with visual acuity loss," Zhang said. "Additional genetic factors and/or environmental factors may be required for progression to advanced age-related macular degeneration."
Age-related macular degeneration is the most common cause of irreversible visual impairment in the developed world. The research article will be available online in November at www.plos.org. More information about macular degeneration is available online at www.moraneyecenter.org.
In addition to Zhang, other investigators contributing to the new findings are from the deCODE Genetics, in Reykjavik, Iceland; Department of Ophthalmology, and Department of Geriatrics, National University Hospital, Reykjavik, Iceland; Faculty of Medicine, University of Iceland, Reykjavik, Iceland; Zhongshan Ophthalmic Center, Sun Yat-sen University, Gaung Zhou, China; Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, China.
Funding for the study was provided by the National Institutes of Health, The Foundation Fighting Blindness, The Ruth and Milton Steinbach Fund, the Ronald McDonald House Charities, the Macular Vision Research Foundation.
For more information (media only), contact:
Kang Zhang, M.D., Ph.D.
Tel 801 587 3026
Pager 801-339-3605 (media only)
Email: kang.zhang@hmbg.utah.edu
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Moran Eye Center PR
Jim Murphy
Tel 801-587-4578
Email: Jim.Murphy@hsc.utah.edu
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