UAB Researchers Find New Biomarker for Age-Related Macular Degeneration

Mar 19, 2019 at 03:41 pm by steve

Cynthia Owsley, PhD

UAB Department of Ophthalmology and Visual Sciences researchers have discovered a genetic biomarker that is associated with age-related macular degeneration and delayed rod-mediated dark adaptation -- the first visual function for incident AMD in older adults with normal macular health and early AMD.

Professors Cynthia Owsley, PhD and Christine Curcio, PhD say there are no current proven strategies for preventing AMD or stopping its progression early in the disease. Two of the strongest genetic associations for age-related macular degeneration are common polymorphisms -- variants in DNA sequence -- at chromosome 1 (CFH) and chromosome 10 (ARMS2).

"We have previously shown that delayed rod-mediated dark adaptation is the first functional risk factor for early AMD," Owsley said. "Delayed dark adaptation means it takes these individuals much longer to adapt to a dark environment than other individuals. This was important, because vision in bright light was known to be relatively preserved late into the disease. Night vision is affected much earlier. "

In the study, Owsley and Curcio established that older adults with delayed dark adaptation are also more likely to have these high-risk genetic polymorphisms at chromosome 1 and chromosome 10.

"This finding was the first genotype-functional phenotype association found in AMD research," Owsley said. "What we find exciting is that the ARMS2 genotype-phenotype association emerges even at pre-clinical stages of AMD. Being able to assess risk at such an early stage could lead to new preventive measures."

Owsley says the ARMS2 gene is poorly understood from a biological standpoint and is also challenging to study because it is not expressed in adults.

"However, our study suggests that making ARMS2 a research priority will lead to new ways of tackling AMD and developing treatments to prevent this disabling disease," she said.

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