A genetic ‘treasure map’

Australian scientists have narrowed their search for the genetic cause of a degenerative eye disease that leads to blindness.

Researchers at the Walter and Eliza Hall Institute of Medical Research have established five key areas, or loci, in the genome that are most likely to affect an individual’s risk of developing macular telangiectasia type two (MacTel).

The disease causes abnormal growth of blood vessels in the macula and is most common in those aged 40 or older. There is no cure or treatment for the condition at present.

Professor Melanie Bahlo told OT that analysis of more than six million genetic markers had identified five loci across the genome that had similar patterns in people with MacTel. Those same patterns were not found in healthy individuals.

“These five genetic risk loci are our treasure map, telling us where to keep digging in order to discover the specific genes implicated in MacTel,” she said. 

Dr Thomas Scerri told OT that the study aimed to confirm the aetiology of MacTel.

“We strongly suspected a genetic link to MacTel, because we have seen several large families where numerous people are affected,” he explained.

The research, which is published in Nature Genetics, also revealed that people with the MacTel genetic risk loci had changes in their metabolism.

Dr Thomas Scerri highlighted to OT that the MacTel risk variants were linked to lower levels of glycine and serine.

Further work will investigate which specific genes and genetic variants are playing a role in the disease.

“In years to come, we hope this work will lead to a better understanding of the disease and ways to predict a person’s risk,” Dr Scerri concluded.