Study shows possible new location for short-sighted gene
Myopia (short sightedness) is a common eye disorder which results in visual impairment. It occurs when light rays entering the eye are focused in front of rather than on the retina. In most cases, myopia is due to an elongated eyeball, referred to as an increased axial length. It can also result from increased steepness of the cornea (corneal curvature) or an increase in the thickness of the lens. It is known to be influenced by genetic and environmental factors, although the cause of myopia is not fully understood.
Recent studies have identified two regions on chromosome 15 which are associated with refractive error (long or short sightedness). CERA’s Associate Professor Paul Baird and Dr Maria Schache aimed to confirm these results using data from the Blue Mountains Eye Study. Their analysis, published in Ophthalmology, investigated the association of these two chromosomal regions with refractive error and the measurements of corneal curvature, anterior chamber depth and the ocular axial length. A total of 1571 unrelated individuals, mainly of European descent, were involved in the study.
Statistical analysis showed a strong association between refractive error and one of the chromosomal regions (15q14); however an association could not be confirmed at the second region (15q25). By undertaking additional genetic analysis, the researchers found that axial length was the most likely cause of refractive error at the 15q14 point.
“The study has shown the importance of the 15q14 chromosome region in myopia and by knowing this, we can start looking for new genes for myopia in that region,” said Associate Professor Baird. To date, there are no known refractive error or axial length genes in this region of chromosome 15.