Gene discovery sheds light on childhood glaucoma

Owen Siggs Jamie Craig
Dr Owen Siggs, left, and Professor Jamie Craig from the Department of Ophthalmology.

Ophthalmology experts at Flinders University have played a pivotal role in discovering a new genetic cause for primary congenital glaucoma – a leading cause of blindness in children.

Glaucoma is a disease linked to increased pressure inside the eye, which can cause irreversible damage to the optic nerve and loss of vision. The disease most commonly affects people over the age of 50, but also affects children and can lead to blindness.

Children usually develop a more aggressive form of the disease, and require multiple operations and a lifetime of daily eye drop medication.

“This study, using samples gathered from across the world, has pinpointed a new genetic cause for congenital glaucoma, a devastating disease that’s extremely difficult to treat,” says Flinders research leader Professor Jamie Craig.

“The discovery paves the way for a new genetic test for children and families with childhood glaucoma, gives new reproductive options to families with a history of the disease and a pathway to better treatments for both adult and childhood glaucoma.”

The disease has now been linked to mutations in the TEK gene which can lead to a poorly formed or even absent cell-membrane receptor protein necessary for proper development of a drainage channel and then elevated eye pressure over time.

The US-led group of collaborating researchers also found that mice with a similar genetic change had a poorly formed drainage canal inside their eye, which normally allows fluid to escape.

Flinders Department of Ophthalmology co-researcher Dr Owen Siggs said the findings would help manage glaucoma at all ages.

“Imagine the gutters on your roof: if the gutter is blocked, the water backs up. The same thing can happen inside your eye,” says Dr Siggs. “The drainage canal in these patients’ eyes simply can’t keep up.”

The research is also an important clue for understanding adult-onset glaucoma, which affects 3% of Australians over the age of 50, or about 60 million worldwide.

Most people with glaucoma use daily eye drops to control pressure inside their eye, with more extreme cases requiring surgery to create an artificial outlet.

“Now that we know more about how the eye’s drainage system develops, we have more potential to improve it in children and adults with glaucoma,” says Dr Siggs. “Making this canal permanently wider could do wonders for someone with glaucoma.”

Led by researchers at the University of Wisconsin-Madison and Northwestern University in the US, the new research paper, ‘Angiopoietin receptor TEK mutations underlie primary congenital glaucoma with variable expressivity’, has been published in The Journal of Clinical Investigation.

Research at Flinders University was supported by the Channel 7 Children’s Research Foundation, the Ophthalmic Research Institute of Australia, and the National Health and Medical Research Council.

In  Australia, tests are offered for several genes already linked to glaucoma – known as CYP1B1, MYOC, FOXC1, PITX2, PAX6, OPTN and TBK1.

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