Researchers in Australia have discovered new genetic areas linked to an increased risk of glaucoma, the leading cause of irreversible blindness worldwide.1 The investigation studied the genetic makeup of nearly 40,000 people, and identified five previously unknown genetic areas linked to an increased risk of primary angle closure glaucoma (PACG).
PACG symptoms occur quickly and require immediate medical attention, according to study coauthor Jamie Craig, PhD, professor of ophthalmology at Flinders University.
“This new discovery provides a handle to gain an understanding of the mechanisms of the disease,” says Craig. “This will help to work out who is at risk of developing angle closure glaucoma so they can have preventative laser treatment before an emergency situation develops. We also expect that, in time, improved understanding of the pathways of this disease will lead to new ways to more effectively prevent and treat this serious condition, so that permanent loss of vision does not occur.”
The genetic analysis is the largest genome-wide association study to date on this condition. It used a combined total of 10,404 cases of angle closure glaucoma and 29,343 normal controls to identify five novel glaucoma markers.
Using the Australian and New Zealand Registry of Advanced Glaucoma, researchers at Flinders University guided international research across 23 countries in the Americas, Asia, Australia, and Europe to make the discovery. Up to 80% of the estimated 15 million people afflicted with PACG live in Asia, where the disease is responsible for a high proportion of blindness.
Glaucoma generally develops later in life, initially causes loss of peripheral vision, and can lead to complete blindness if untreated. Angle closure glaucoma is a less common form of the disease than open angle glaucoma. It is caused by blocked drainage canals in the eye and is characterized by a narrow angle between the iris and cornea.
“With PACG it comes on quite rapidly, so patients are aware something is happening. But if something is not done quickly, they can lose their vision,” says Craig. “All types of glaucoma have a strong hereditary or family influence, and if there are any cases of glaucoma in the family, then people should be checked every 2 years from the age of 40.”
- Khor CC, Do T, Jia H, et al. Genome-wide association study identifies five new susceptibility loci for primary angle closure glaucoma. Nat Genet. Published online in advance, April 4, 2016; doi: 10.1038/ng.3540.