Page 66 - life-in-naples-march-2016

BASCOM PALMER EYE INSTITUTE

AT THE FOREFRONT

OF GENETIC RESEARCH

FOR AGE-RELATED MACULAR DEGENERATION

by Jaclyn L. Kovach, MD

J aclyn L. Kovach, MD and Stephen G. ophthalmologists at the University of Miami.
Schwartz, MD, MBA at the University The International AMD Genomics
of Miami Miller School of Medicine’s
Consortium, which includes 26 centers

Bascom Palmer Eye Institute and the John worldwide, collected and analyzed the genetic

P. Hussman Institute for Human Genomics are part data from 43,566 people of predominantly

of a consortium that has significantly expanded the European ancestry to systematically identify

number of genetic factors known to play a role in common and rare variations in genetic coding

age-related macular degeneration (AMD), a leading — called variants — associated with AMD.

cause of vision loss among people age 50 and older. Common variants generally have an indirect

Supported by the National Eye Institute, part of the association with a disease. Rare variants,

National Institutes of Health, the findings may help by contrast, are more likely to alter protein

improve our understanding of the biological processes expression or function and therefore have

that lead to AMD and identify new therapeutic STEPHEN G. SCHWARTZ, MD, MBA a direct or causal association with a disease.
targets for potential drug development. Rare variants were defined as those found in

AMD is a progressive disease that causes the death less than one percent of the study population.

of the retinal photoreceptors, the light-sensitive cells The study included about 23,000 participants with AMD and 20,000

at the back of the eye. The most severe damage occurs without it. Researchers analyzed DNA samples from both groups,

in the macula, a small area of the retina that is needed surveying most of the genome, but also focusing on distinct loci already

for sharp, central vision necessary for reading, driving known or suspected to be associated with AMD. Next, they compared the

and other daily tasks. There are currently no Food participants’DNA to a reference dataset called the 1,000 Genomes project,

and Drug Administration-approved treatments for yielding more than 12 million genetic variants of potential interest. Finally,

the more common form of advanced AMD, called they went back to the participants’ DNA samples, looking at all 12 million

geographic atrophy or “dry” AMD. While therapies variants, to see if any were found more or less often in people with AMD

for the other advanced form, neovascular or “wet” than those without it.

AMD, can successfully halt the growth of abnormal, The study findings also bolster associations between AMD and two

leaky blood vessels in the eye, the therapies do not genes, CFH and TIMP3, which had each previously been linked to AMD.

cure the condition, nor do they work for everyone. CFH was the very first disease-linked gene to be found through a genome-

Up to this point, researchers had identified 21 wide association study. TIMP3 had earlier been linked to Sorsby’s fundus

regions of the genome — called loci — that influence dystrophy, a rare disease that is similar to AMD clinically, but which tends

the risk of AMD.The new research,recently published to affect people before the age of 45.

online in Nature Genetics, raises the number of loci For the first time the researchers also identified a variant specific to the

to 34. Jaclyn L. Kovach, M.D., associate professor neovascular form of AMD, which may point to reasons why therapy for

of clinical ophthalmology at Bascom Palmer Eye this form of AMD is effective for some people but not everyone.

Institute, and Stephen G. Schwartz, M.D., associate “This pivotal paper lays the groundwork for future sight-saving

professor of ophthalmology and Medical Director at treatments using genetic based therapies for age-related macular

Bascom Palmer Eye Institute at Naples were the lead degeneration,” said Kovach.

66 Life in Naples | March 2016