14 September 2010
Myopia Gene Found; Drug Is Being Tested
Scientists have discovered a gene that causes myopia or shortsightedness, a breakthrough which they claim could pave the way for treatment for the most common eye disorder in the world.
Now, an international team, led by the King’s College, London, has identified the gene, known as RASGRF1, which plays a key role in the development of the eye and the passing of visual signals to the brain for processing.
According to the scientists, within just ten years, a drug that prevents short–sightedness or stops it in its tracks could be in widespread use, making the wearing of glasses negligible, the British media reported. To find the gene, the scientists compared the DNA of more than 4,000 British twins. They then confirmed their results by studying the genetics of another 13,000 British, Dutch and Australian individuals.
Some 45% of Britons have the rogue gene and those who have two copies of it are almost twice as likely to be shortsighted as those who are free of it. "We have known for many years that the most important risk factor for being shortsighted is having parents who are shortsighted, and for the first time we are identifying genes that may be involved in passing on this susceptibility," said Dr Pirro Hysi, who led the team.
In fact, the scientists found several distinct spellings of DNA code near the RASGRF1 gene that had a strong association with focusing errors. Team member Terri Young of Duke University in North Carolina, said: "The RASGRF1 provides a novel molecular mechanism to study so that we can work to prevent the most common cause of visual impairment."
"Because RASGRF1 is highly expressed in neurons and the retina, it is crucial to retinal function and visual memory consolidation," said Young. When the scientists created mice that were missing the correct gene, these mice showed changes in their eye lenses. "This was biologically convincing. The RASGRF1 provides a novel molecular mechanism to study so that we can work to prevent the most common cause of visual impairment," said Young.
Young has also led a team that found a different gene – CTNDD2 – related to myopia in Chinese and Japanese populations. The study has been published in Nature Genetics. While many cases of myopia are mild, 2–3% are pathological cases with retinal detachment, premature glaucoma, macular bleeding, and glaucoma leading eventually to blindness, said Young, who has spent over a decade studying the severe form of myopia.