Icelandic genetics company DeCODE announced yesterday the discovery of two common single letter variations (SNPs) in the sequence of the human genome that appear to account for virtually all cases of a major subtype of glaucoma. <?xml:namespace prefix = o ns = “urn:schemas-microsoft-com:office:office” />
The research was conducted in a collaboration between scientists from deCODE genetics and academic colleagues from the <?xml:namespace prefix = st1 ns = “urn:schemas-microsoft-com:office:smarttags” />National University Hospital in Reykjavik and Uppsala University in Sweden. The results were published yesterday in the online edition of the journal Science.
Glaucoma is one of the most common causes of blindness worldwide. There are various types of glaucoma, all of which lead to damage in the optic nerve and progressive loss of vision. Exfoliation glaucoma is caused by the buildup of fibrous deposits on the surfaces on the front of the eye. Between ten and 20 percent of people over the age of 60 are believed to have some degree of exfoliation syndrome, and perhaps more than half of these individuals will go on to develop exfoliation glaucoma.
Approximately 25 percent of those in the Icelandic and Swedish study were found to have two copies of the highest risk variant, putting them at approximately 100 times the likelihood of developing exfoliation glaucoma (XFG) as are individuals with the low risk version of the same SNP.
“This discovery is remarkable and important because the genetics has led us directly to what appears to be the sole cause of a devastating common disease. The risk conferred by these variants is such that it accounts for virtually all cases of exfoliation glaucoma, meaning that if we can neutralize the impact of these variants we might eliminate the disease […] We plan to conduct additional studies to examine how we can take advantage of this finding to begin drug discovery,” said Kári Stefánsson, CEO of deCODE in a statement from the company.