Gene is associated with increased risk of precursor of macular degeneration A variant in a gene called Complement Factor H (CFH) appears to contribute to the increased risk of advanced age-related macular degeneration (AMD) largely or entirely through its impact on the development of a precursor of advanced AMD called soft drusen (small yellowish, extracellular deposits of lipid, protein and cellular debris in the back of the eye), according to a multinational team of researchers.
Several research groups recently showed that CFH increases the risk for advanced AMD. However until this study, the relationship between CFH, soft drusen, and advanced AMD was unclear.
In an article to be published online on November 29 by PLoS Medicine, the researchers working at the deCODE genetics Inc., Reykjavik, Iceland, the Moran Eye Center and Eccels Institute of Human Genetics of the University of Utah, USA, and the University of Iceland, found that CFH is a major risk factor for soft drusen. The researchers looked at the CFH gene and its relationship with the presence of soft drusen and AMD in 581 Icelandic patients with advanced and 435 with early AMD, and also 322 US patients with advanced and 109 with early AMD.
AMD is the most common cause of visual loss and is preceded by formation of soft drusen. However, only a portion of patients who develop soft drusen will go on to develop advanced AMD. "We have discovered that the CFH variant is a major risk factor for soft drusen, but does not appear to determine who ultimately progresses to advanced AMD, as previously proposed" , said Dr. Kristinn P. Magnusson, who led the deCODE genetics research team with Dr. Jeffrey Gulcher. Dr. Kang Zhang led the University of Utah team. The authors conclude that 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.