In a study of more than 330,000 people, five genetic variants and being educated to university level were together linked to short-sightedness
17 November 2022
Five genetic variants may be linked to the onset of short-sightedness in people who study to university level. The discovery could help to identify children who are more likely to develop the condition so that interventions can be put in place to help prevent its onset, such as spending more time outdoors.
Short-sightedness, also called myopia, is a common condition that affects a person’s ability to see distant objects.
Prior to this research, genetics and lifestyle factors were thought to affect our myopia risk. Rosie Clark at the University of Bristol, UK, and her colleagues wanted to better understand how these factors interact to influence the condition’s onset.
The team conducted a genome-wide association study (GWAS) on people with European ancestry. These scan markers across genomes to find any variations associated with a particular condition.
The researchers first looked for genetic variants linked to myopia in more than 88,000 adults, assessing whether the participants had myopia according to a standard eye test.
They identified 19 variants that are linked to different severities of myopia when they interact with certain environmental factors or other genes.
Finally, the team analysed these variants in more than 250,000 people who wore glasses. “We generally took people who said they started wearing glasses before 25 as a sign they had myopia,” says Clark.
The researchers were particularly interested in a potential three-way link between genetic variants, education level and myopia.
The participants therefore also reported whether they went to university. “Many studies have shown the link between education and myopia,” says Clark. More time in education is usually linked to more time indoors, she says. We know that frequently spending time outdoors may prevent myopia’s onset or stop it worsening.
The results suggest five of the 19 genetic variants are affected by education level and together these are linked to myopia.
Two of the variants were identified in a previous study looking at myopia in people of east Asian ancestry.
Some of these five variants are linked to the visual system, but it is unclear how they may cause myopia, says Clark.
The findings may not apply to people of non-European descent, she says. About 30 per cent of children in the West develop myopia compared with 80 per cent of children in east Asia, says Clark.
Nevertheless, identifying these genetic variants could one day help researchers determine a child’s myopia risk.
“Maybe the child could learn outdoors or we’re going to make sure the child takes regular breaks and has time [during the school day] to go outside,” says Clark.
Ian Morgan at the Australian National University in Canberra is unsure whether this research has practical applications. “While this is beautiful scientific work that certainly adds to our understanding, the bottom line is that it is not clear that genetic analysis is leading to useful interventions to control myopia,” he says.
Journal reference: PLoS Genetics, DOI: https://doi.org/10.1371/journal.pgen.1010478
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