CFH and Macular Degeneration
This web page was produced as an assignment for Gen677 at UW-Madison Spring 2010.
Please click on images themselves for a larger view.
CFH and Age-Related Macular Degeneration
The leading cause for blindness for Americans over 55 years old is Age-related macular degeneration (AMD) (1). It affects over 10 million Americans. AMD causes 8.7% of blindness in the world, making it the third most common cause (2).
AMD is a progressive disease of the macula of the eye. The macula is responsible for the eye’s ability of focus on the center of vision and is located at the back of the eye. Individuals with AMD can use their peripheral sight to see, but as the disease progresses, the portion of usable peripheral sight decreases as more of the macula is damaged (1).
Two Types of AMD
There are two types of macular degeneration, wet (also known as neovascular) and dry (atrophic) (4). Most (90%) people with macular degeneration have dry AMD (1). There are treatments available for wet AMD but not dry. Wet AMD is caused when abormal blood cells behind the retina leak blood and other fluids, altering the position of and damaging the macula. Dry AMD is caused by damage to the macula's light sensitive cells and is often accompanied by drusen (yellow residue beneath the retina) (4).
AMD Gene (CFH)
In 2005, it was discovered that having a particular variant of the gene complement factor H (CFH) increases the likelihood of developing AMD. It is suspected that CFH is responsible for 43% of AMD cases. CFH is located on chromosome 1q32 and is 4200bp (the protein is 1,231 amino acids long). Complement factor H is involved in the inflammation response of the innate immune system.
The top eye is a diagram of a healthy eye with a healthy macula. The bottom eye is a diagram of an AMD eye with a degenerated macula. Diagram taken from http://www.sfn.org/index.cfm?pagename=brainbriefings_agerelatedmaculardegeneration
What an individual with AMD would see
Photo taken from http://www.lowvisionclub.com/articles/seewhatisee.html
References
- Macular Degeneration Partnership. "What is AMD?" AMD.org. Web. 3 Feb. 2010.
- Ayoub, T., and N. Patel.2009. Age-related macular degeneration. JRSM. 56-61.
- Haines, J. L., M. A. Hauser, S. Schmidt, W. K. Scott, L. M. Olson, P. Gallins, K. L. Spencer, S. Y. Kwan, M. Noureddine, J. R. Gilbert, N. Schnetz-Boutaud, A. Agarwal, E. A. Postel, and M. A. Pericak-Vance. 2005. Complement Factor H Variant Increases the Risk of Age-Related Macular Degeneration. Science. 308:419-421.
- "Facts About Age-Related Macular Degeneration [NEI Health Information]." National Eye Institute [NEI], of the U.S. National Institutes of Health. Web. 09 Feb. 2010. <http://www.nei.nih.gov/health/maculardegen/armd_facts.asp>.
This website is dedicated to my amazing grandmother
