May 3, 2013
Genetic Mutation’s Role In High-Grade Myopia Examined
redOrbit Staff & Wire Reports - Your Universe Online
Researchers have discovered a link between nearsightedness and mutations in a gene partially responsible for the regulation of copper and oxygen levels in eye tissues, according to a paper published in Thursday´s edition of the American Journal of Human Genetics.
Nearsightedness, which is also known as myopia, is a condition which results when a person´s eye is too long or there is too much curvature in their cornea, which keeps light entering the eye from focusing properly.
A more severe form of the condition, which affects up to two percent of people in the US and is particularly common in Asian population, is known as high-grade myopia and can result in an increased risk of other serious eye conditions such as retinal detachment, cataracts and glaucoma.
Previous research has suggested that nearsightedness is caused by a combination of genetics and environmental influences, such as an overabundance of reading. While the condition has been known to be inherited in families, the specific genetic factors involved have remained unclear — leading a team of experts from Duke University Medical Center to further explore the issue by studying families suffering from high-grade myopia.
“This is the first time a gene mutation for autosomal dominant nonsyndromic high-grade myopia in Caucasians has been discovered,” senior author Terri Young, a professor of ophthalmology, pediatrics and medicine at the Duke Eye Center, Duke Center for Human Genetics and the Duke-National University of Singapore Graduate Medical School (Duke-NUS), said in a statement. “Our findings reflect the hard work and collaboration of our international research team.”
Young and her colleagues performed next-generation deep sequencing on four members of an 11-member American family of European descent. By analyzing DNA extracted from their blood and saliva, Young´s team identified that mutations in the SCO2 gene were common in family members with high-grade myopia, but absent in those that did not suffer from the condition.
They went on to identify four mutations in the SCO2 gene in an additional 140 people with high-grade myopia, and once those mutations were identified, the researchers examined human eye tissue. In doing so, they verified that this particular gene was expressed in areas of the eye linked to being nearsighted. They then performed experiments on mice which provided further evidence that the gene could play a role in the development of myopia.
“Our findings, plus information from the literature, suggest that copper deficiency could predispose people to develop myopia,” Young explained. “While this wasn't directly tested in this study, it's possible that our diets — which are deficient in a number of minerals and vitamins — play a role, and it may be something as easy as taking a supplement with copper that helps thwart the development of myopia.”