Scientists at deCODE genetics and academic colleagues from Iceland, China, Sweden, the United Kingdom, and Australia today report the discovery of the most important single-letter variation (SNP) in the sequence of the human genome yet associated with risk of primary open-angle glaucoma. This is the most common form of glaucoma and a major cause of blindness worldwide.
The SNP on chromosome 7q31 is common among Europeans, with approximately 6% of people of European ancestry carrying two copies of the at-risk version, putting them at roughly 60% greater risk of developing the disease than those who carry none. But among Chinese, the impact of the SNP is markedy different. In study groups from Hong Kong and Shantou, the at-risk version of the SNP is shown to be carried by less than 1% the population, but each copy carried confers a more than 5-fold increase in risk. The SNP is near the genes encoding caveolin 1 and 2, membrane proteins that are expressed in the meshwork that drains fluid from the eye, a process that if disturbed can increase pressure on the optic nerve and lead to glaucoma.
“The key to reducing the personal and public health impact of glaucoma is early diagnosis and treatment to slow the loss of sight. Discoveries such as today’s, which follows on our previous landmark findings in exfoliation glaucoma, are important because we can fold them directly into tests to target screening and to detect and treat more disease earlier. Moreover, among Chinese this latest SNP alone can define a small fraction of the population that should be very carefully screened. This underscores the value of being able to systematically analyze the impact of genetic risk factors across continental ancestries. Not only are these markers medically useful, they also tell us a bit about evolution and the spread of humanity across the globe,” said Kari Stefansson (pictured), deCODE’s Executive Chairman and President of Research and senior author of the study.
Illustration: deCODE Genetics.
deCODE Genetics News Release (09/13/10)
PR Newswire (09/13/10)
Abstract (Nature Genetics; 42, 906-909 (09/12/10))