S’pore scientists identify new genes linked to glaucoma

SINGAPORE: Singapore scientists have identified three new genes associated with Primary Angle Closure Glaucoma (PACG), a leading cause of blindness in Chinese.

This is the first discovery made in the world which links glaucoma to genetics.

A 2010 study showed that glaucoma affected 60 million people worldwide, and about half of them are from Asia.

Glaucoma occurs when there is nerve damage from pressure in the eyeball.

The disease can be divided into two main categories, Open Angle Chronic Glaucoma and Primary Angle Closure Glaucoma (PACG). The angle refers to the area between the iris and cornea, through which fluid must flow to escape via the trabecular meshwork.

Nine in 10 Asians who have glaucoma suffer from PACG.

PACG is a type of glaucoma where visual loss progresses very quickly. It is usually more prevalent among those aged 60 years or older.

PACG is also more common in Asia than the west.

Professor Aung Tin, deputy director, Singapore Eye Research Institute, said: "One of the genes affects vascular permeability, and the other gene is a collagen—related gene. But the third gene, we do not know what it does."

Having the first gene makes a person 30 per cent more susceptible to the disease.

The second gene, by 50 per cent.

If a person has all three genes, the risk may increase to up to 300 per cent.

PACG was also found to be the leading cause of blindness in Chinese people.

This is because of an anatomical risk, present in the eyeball of a Chinese, where the angle between the iris and the cornea is narrower than a person of another race. This puts them at a higher risk of contracting the disease.

The research team said the glaucoma research study will be the start of more to come, especially in dealing with the treatment of PACG.

Professor Aung Tin said: "We hope that with these findings... we will be able to better identify people at risk for the disease, so that we can intervene, and do a preventive treatment for them. We (also) hope that these findings will lead us to improve our understanding of disease mechanism and causation so that in the future we can develop novel therapies for the condition."

The team hopes that future glaucoma—related treatments can be made based on individual genetic profiles.

— CNA/cc