Genes linked to glaucoma

Glaucoma is a disease associated with a damaging build-up of fluid in the eye. It is the leading cause of irreversible blindness in the world. One of the two main forms of glaucoma, primary angle closure glaucoma (PACG), results when the eye's iris obstructs the part of the eye that drains fluid away, pressure increases, eventually damaging the optic nerve.

An international team of researchers, including three from King Saud University, Riyadh, performed a genome-wide association study (GWAS) to look for genetic factors behind PACG, which is most prevalent in Asia. They performed analysis on 3,771 glaucoma patients and 18,551 healthy controls over two stages, publishing their results in Nature Genetics.

The researchers worked with patients recruited in Singapore, Hong Kong, India, Malaysia, Vietnam, China and Saudi Arabia. They identified three new genetic regions for PACG in the genes PLEKHA7, COL11A1 and the third between PCMTD1 and ST18.

The gene PLEKHA7 encodes a protein complex that regulates cellular permeability and may thus play a role in the abnormal fluid retention in the eye. COL11A1 is expressed in the trabecular meshwork, the tissue responsible for draining aqueous humour. A mutated version of the gene may make eyes hyperopic and predisposes a person to PACG.

The third locus, found between PCMTD1 and ST18, encodes a protein of unknown function. "We can perform the knock-in and knock-out gene experiment to observe the change of the expression of corresponding proteins and clarify its functions in the development of PACG," says Ningli Wang, co-author of the paper.

The researchers suggest that further genetic study of PACG could help draw a genetic profile to diagnose and, eventually, treat the disease. "With the new discovery of the PACG loci, we can reassess our diagnosis and decide whether surgery is necessary for the PACS patients," adds Wang.

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