Feb 27 2008
Variations in genes that control the production of chemicals involved in inflammation may hold the clue to age related macular degeneration, or AMD, suggests research published ahead of print in the British Journal of Ophthalmology.
AMD affects the centre of the retina (macula) at the back of the eye, which is used for fine central vision tasks, such as reading and driving.
It is progressive and most common in the elderly, among whom it is a major cause of untreatable blindness in developed countries.
The UK researchers from the University of Southampton looked for evidence of four variations in genes controlling the production and suppression of cytokines - powerful chemicals involved in inflammatory processes in the body.
They took DNA samples from 478 people with AMD and 555 people with no signs of the disease. All of them were aged over 55.
One of the genetic variants (251A/T), which is associated with a gene that boosts the production of the cytokine interleukin 8, or IL-8 for short, was significantly more common among the patients with AMD. This held true even after taking account of age, sex, weight, and smoking - known risk factors for AMD.
The IL-8 251A/T genetic variation has been previously linked to several inflammatory diseases and cancer.
If repeated in larger studies, the authors suggest that their findings might lead to the possibility of genetic screening for AMD and the development of biological agents to control it.
In an accompanying editorial, US eye specialists from the National Institutes of Health and the University of Michigan, sound a note of caution, reiterating that further studies will be needed before a direct cause and effect can be established.
Nevertheless, the explanation is plausible, they say. The development of AMD has been linked to an interplay between genetic and environmental factors.
Natural changes as a result of ageing and the accumulation of oxidative stress seem to be the initial triggers for the disease, which worsens as a result of immune system activity, they suggest.
Click here to view full paper: https://bjo.bmj.com/
Click here to view full editorial: https://www.bmj.com/company/