Genetics important in age-related macular degeneration

Reported by Susan Aldridge, PhD, medical journalist

A new study suggests that genetics could play an important role in the leading cause of blindness in older adults.
Age-related macular degeneration (AMD) occurs when the retina of the eye deteriorates and starts to impair vision. It has not been clear what the relationship between genes and environment is in this disorder. A team at Harvard Medical School now sheds new light with a study of twins born between 1917 and 1927.

They found that in a group of 840 twins, 331 had no sign of AMD, 241 had early signs, 162 had intermediate AMD and 106 had advanced disease. The researchers compared the rates of disease between identical and non-identical twins. Identical twins share a genetic background, so if a disease were wholly genetic you might expect one twin to have a disease if the other one did.

Analysis of these results suggested that genetic factors do play a substantial role in AMD, explaining between 46 to 71 per cent of the overall severity of the disease. However, it is not yet known which genes might be involved in the disorder - this is the subject for further research.

Source
Archives of Ophthalmology March 2005 Volume 123 pages 321-327

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