Genes May Predict Elderly Blindness Risk

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Age-related macular degeneration (AMD) involves damage to the inner lining of the eye and can lead to visual impairment and even legal blindness.

"There are several million people who have the earlier-intermediate stages of AMD once they reach the age of 75 or older, but [only] 6 to 8 percent of individuals have advanced disease, so the question is, how do we predict or identify those people who are at higher risk?" Seddon said.

AMD has previously been associated with variations in two genes: CFH and LOC387715. But previous studies exploring this relationship had been cross-sectional in nature, not prospective as the current one is.

For this study, Seddon and her colleagues looked at almost 1,500 white adults aged 55 to 80 with the earlier intermediate signs of macular degeneration. During an average of more than six years of follow-up, 281 individuals progressed to advanced AMD in one or both eyes.

Genotypic analysis revealed that two specific genetic polymorphisms -- CFH Y402H and LOC387715 A69S -- were linked with progression to more advanced AMD.

The risk of progression was 2.6 times higher for those with the CFH variant and 4.1 times higher for those with the LOC387715 variant, after controlling for other factors.

For people who had one of the genotypes, smoking and being overweight increased the risk 19-fold, making a strong argument for lifestyle changes in people who are identified as having the genetic risk factors.

More information

For more on AMD, visit the U.S. National Eye Institute.