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Age Related
Macular Degeneration - Genetics link could increase Risk
March 6th, 2006
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Eye |
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A study conducted at the Columbia University Medical Center found two
genes, Factor H and Factor B, may increase the occurrence of age-related
macular degeneration (AMD) in 74% of these patients. There is an
estimated 10 million individuals in the United States that have AMD.
The study was first published in Nature Genetics and found that three
out of four AMD patients had either one or both of these genes. This
study found that the Factor H gene showed a considerably higher risk for
developing AMD. People that have a variation of the Factor H are not
able to control inflammation. Factor H gene when working properly works
by telling a protein to stop an immune response when the infection is
gone.
The researchers realize that even though Factor H increases the AMD
risk, there is not a clear reason why some people that have the
variation don’t develop AMD. In their research, the scientists found
that there were 29 percent of people that had the Factor H risk variant
and were not diagnosed as having AMD.
The scientists wanted to look further into any other genes that worked
in the same pathway of the immune system response because of the Factor
H variant carriers that did not have AMD. They analyzed 1,300 people
for additional genetic information. The researchers found Factor B was
the major modifier for AMD. Factor B is an activator for the immune
system response. The researchers believe that since Factor H is the
opposite as Factor B, the genes can balance each other and prevent the
disease from progressing in some people.
"I am not aware of any other complex disorder where nearly 75 percent of
genetic causality has been identified," said Dr. Rando Allikmets, Ph.D.,
the Acquavella Associate Professor in Ophthalmology, Pathology and Cell
Biology at Columbia University Medical Center, who is senior author of
the paper.
"These findings are significant because they absolutely confirm the
roles of these two genes and, consequently, the central role of a
specific immune response pathway, in the development of AMD. We
confirmed this association not just statistically and genetically but,
most importantly, pinpointed the biological origin of the disease,"
stated Dr. Allikmets. "In just a few short years, we've gone from
knowing very little about what causes AMD to knowing quite a lot. We now
have clear targets for early therapeutic intervention."
The researchers may have new understandings of the genetic relationship,
but further research needs to be understood in how to manage the immune
system. Once the researchers understand how to prevent inflammation
they will be able to prevent damage to the eye from occurring.
By
Nicole Wilson
Best Syndication Staff Writer
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