Researchers discover genes strongly associated with PACG

An international research collaboration has revealed eight genes strongly associated with primary angle-closure glaucoma (PACG), the most prevalent form of glaucoma in Singapore and Asia, according to a joint press release by researching organisations Tuesday.

The collaboration was jointly led by Dr Khor Chiea Chuen from A*STAR's Genome Institute of Singapore (GIS) and Prof Aung Tin from Singapore Eye Research Institute (SERI), Singapore National Eye Centre (SNEC) and National University of Singapore (NUS).

The eight genes provide unexpected insights into the disease process of glaucoma, and how the shape of the eye could contribute to the disease even in currently healthy, asymptomatic people.

The study involved more than 10,000 patients from 24 countries and the findings were reported in the prestigious scientific journal Nature Genetics. This paves the way to identify potential new drug targets to treat glaucoma, and build up genetic predictors that could help to screen and to direct treatment for individuals at risk of becoming blind from glaucoma, according to the release.

Although it is preventable, glaucoma is the most common cause of irreversible blindness worldwide. PACG is responsible for a high proportion of blindness in Asia; with up to 80 percent of the estimated 15 million people afflicted with PACG living in Asia.

Epidemiological risk factors of PACG include advancing age, the female gender, as well as being of East Asian ethnicity. There are also ocular risk factors such as hyperopia and smaller anatomical dimensions of the eye.

Having seen glaucoma patients at the SNEC and SERI for more than 20 years, Prof Aung noticed that PACG is fairly common in elderly Singaporean Chinese, and that the disease appears to run in families, thus raising the possibility that there could also be a hereditable basis for PACG.

For much of the past decade, the search for susceptibility genes for PACG has not been fruitful mainly because earlier genomic technology and methods did not allow deep and broad searches across the entire genome to occur concurrently.

Recent advances in genomic technology have made possible an unprecedentedly broad and unbiased search for genes associated with disease in the human genome, sparking GIS and SERI/SNEC to collaborate again in the search for human genetic variants which could cause PACG.

"It was very exciting but also challenging to coordinate this project from Singapore as it involved so many samples from more than 100 centres in 24 countries around the world. We hope our findings will be a major contribution to the understanding of PACG, which is a particularly important cause of glaucoma and visual loss/blindness in Singapore and Asia," said Aung. Enditem