Link Found Between Mitochondrial DNA And Macular Degeneration
May 15th, 2008 | by admin |Researchers from Vanderbilt University have found that geneticvariation in mitochondrial DNA can affect a person’s risk of developingage-related macular degeneration (AMD). The results of this first studythat analyzes the relationship between AMD and changes in themitochondrial genome are published in the open-access journal PLoSONE.
AMD is the chief cause of blindness in Caucasians who are over the ageof 50 and affects as many as 10 million people in the United States. Itis a condition characterized by thinning and sometimes bleeding of thecenter of the inner lining of the eye (the macula area of the retina).This results in severe vision loss that makes activities such asreading, driving, watching television, and identifying faces extremelydifficult or impossible.
Mitochondria - basic components of many types of cells - are known asthe cell’s “power plants” and generate most of the chemical energy usedin the cell. Though most of the DNA in a cell is contained in thenucleus, the mitochondria also have a DNA. Lead author of the studyJeff Canter, M.D. M.P.H. (Center for Human Genetics Research) says thatpeople are usually not aware that humans have two genomes. “We have thenuclear genome - the ‘human genome’ - that makes the cover of all themagazines, and then we also have this tiny genome in mitochondria inevery cell.”
Canter and colleagues set out to investigate a possible associationbetween AMD and a specific variation in the mitochondrial genome thatoccurs in about 10% of Caucasians called mitochondrial haplogroup T.”We suspect that this variant will be one of a small group ofimportant genetic variations that underlie AMD,” said Canter.”By knowing this, we have a better chance of predicting accurately whowill get the disease.”
Canter remarked that the genetics of AMD has become a popular researcharea. Co-author Jonathan Haines, Ph.D. (Center for Human GeneticsResearch), an expert in AMD genetics and treatment, recently led a teamthat found a variation in the Complement Factor H (CFH) gene thataccounted for up to 43% of AMD. In addition, researchers have linkedAMD to variations in ApoE2 and a gene called LOC387715 on chromosome10. Haines and colleagues reported that smoking and variationson the chromosome 10 gene raised the risk of AMD.
This current study not only analyzed the mitochondrial genome but alsoinvestigated variation in these nuclear genes in 280 AMD cases and 280age-matched controls. The researchers were able to demonstrate that thevariation in mitochondrial genome was independent of the known nuclearfactors.
Haines said that, “We’re at the stage where we can use geneticinformation to predict who is likely to develop AMD wellbefore they actually develop it. Now we can conduct trials ofpreventive treatments something’s that never been possible before.”
Canter added that these findings could lead to personalized medicine.”I can see a day when physicians order genotyping on patients at acertain age to determine risk for AMD and put things in place- dietary changes, antioxidants, increased screening - that couldprevent the disease.” Canter emphasized that variation in themitochondrial genome has been linked to a wide variety of diseasesincluding.
Regarding the fact that mitochondrial variation has been associatedwith neurodegenerative diseases like Parkinson’s andAlzheimer’s as well as breast cancer and trauma survival, Canterconcludes: “It’s important to realize that there’s another genome inthe mitochondria, and even though there are not many genes there,they’re important.”
Mitochondrial DNA Polymorphism A4917G Is IndependentlyAssociated with Age-Related Macular Degeneration
Canter JA, Olson LM, Spencer K, Schnetz-Boutaud N, AndersonB, et al.
PLoS ONE (2008). 3(5): e2091.
doi:10.1371/journal.pone.0002091
ClickHere to View Article
About PLoS ONE
PLoS ONE is the first journal of primary researchfrom all areas of science to employ both pre- and post-publication peerreview to maximize the impact of every report it publishes. PLoSONE is published by the Public Library of Science (PLoS), theopen-access publisher whose goal is to make the world’s scientific andmedical literature a public resource.
About the Public Library of Science
The Public Library of Science (PLoS) is a non-profit organizationof scientists and physicians committed to making the world’sscientific and medical literature a freely available public resource.For more information, visit http://www.plos.org
Written by: Peter M Crosta
Copyright: Medical News Today
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