Researchers at Columbia University Medical Center discovered a gene that causes myopia, also known as nearsightedness. Carrying the gene variant can increase one's likelihood of developing the visual condition by five times.
Myopia, or nearsightedness, is a vision condition in which the objects are seen clearly when close, but appear blurred when at a distance. Nearsightedness is one of the refractive errors that are common in the United States which can be corrected by glasses, contact lenses, or refractive surgery.
Andrei Tkatchenko, study leader and an assistant professor of Ophthalmic Sciences at Columbia University, worked with his colleagues in analyzing the data of approximately 14,000 people. They discovered that those who have the gene variant called APLP2 were five times more likely to become nearsighted in their teens when they read at least an hour per day during their childhood. Those who carry the gene but don't read that much, on the other hand, had no risk.
"We have known for decades that myopia is caused by genes and their interactions with environmental factors like reading and nearwork, but we have not had hard proof. This is the first known evidence of gene-environment interaction in myopia," Dr. Tkatchenko said in a university news release.
The researchers admitted that further study is needed because they weren't able to determine how APLP2 causes nearsightedness. Their assumption is that the gene could be increasing the amount of the APLP2 protein in the eye which causes excessive elongation.
Once the theory is proven, it will pave the way for the development of a therapy that could correct this visual condition or prevent its progression. The treatment will take years to be developed though because the researchers still need to figure out how to reduce the gene APLP2 in the eye.
"Once the eye has elongated, you cannot shrink it, so we would need to identify kids with genetic risk factors as they enter school," Dr. Tkatchenko said. "That's not yet possible because there are probably hundreds of genes that can cause myopia, and so far, only 25 candidates have been identified. The high-risk variant of APLP2 is relatively uncommon, occurring in about 1 percent of the population."
The study was published in the August 27 issue of PLOS Genetics.
