Oct. 7, 2008
Age-related macular degeneration: New gene association identified
A new genetic association with the condition age-related macular degeneration (AMD) is reported in an article published Oct. 7 early online in the journal The Lancet and will appear in an upcoming print edition. The article is written by Sarah Ennis and Andrew Lotery at the University of Southampton, United Kingdom, and their collaborators, Robert Mullins and Edwin Stone at the University of Iowa.
AMD is the most prevalent form of visual impairment and blindness in developed countries. A recent study, known as the Rotterdam Study, showed that 64 percent of people age 80 and older have signs of the disease, and approximately 12 percent of this age group have AMD so severe it causes them to go blind. The total yearly costs of health-care usage are seven times higher for patients with AMD than for controls, largely attributable to the decreased independence of affected individuals and increased need for assistance with daily living.
The researchers initially looked at a UK sample of patients with AMD (479) and controls (479) and screened 32 genes potentially involved in the condition. They found an association with the SERPING1 gene, which is involved in production of proteins for the "complement" system within the eye that helps clear foreign material and infection.
By analyzing single base pair mutations, the group initially identified a single variant within the SERPING1 gene in which frequencies of the variant forms were significantly distorted in patients compared to controls. The researchers then replicated their findings in a separate cohort in the United States of 248 patients and 252 controls, and further verified their finding by conducting a secondary high-density analysis that revealed an additional five variants in the SERPING1 gene all associated with AMD.
The authors concluded, "Our study shows a strong association between age-related macular degeneration and SERPING1, with supporting evidence from an independent replication and a secondary high-density scan of the gene ... , genetic variation in SERPING1 may implicate the classic pathway of complement activation in AMD ... . Our findings add to the growing understanding of the genetics of age-related macular degeneration, which should ultimately lead to novel treatments for this common and devastating disease."
Edwin Stone, M.D., Ph.D., UI professor of ophthalmology and visual sciences and a Howard Hughes Medical Institute investigator, who led the portion of the study in the United States said, "The list of genes involved in macular degeneration is growing steadily, and our understanding of the disease mechanisms increases with each one. We are hopeful that studies like this will ultimately lead to a preventive treatment for this devastating disease."
In an accompanying comment, Caroline Klaver, Erasmus Medical Centre, Netherlands, and Arthur Bergen, Netherlands Institute for Neurosciences, Netherlands, said that the next steps in the research should include replication of the study's findings in large independent cohorts as well as functional studies.
STORY SOURCE: University of Iowa Health Care Media Relations, 5141 Westlawn, Iowa City, Iowa 52242-1178
MEDIA CONTACTS: Joe Schmidt, UI Department of Ophthalmology and Visual Sciences, 319-384-8529 (office), 434-825-7375 (cell), firstname.lastname@example.org; Becky Soglin, UI Health Care Media Relations, 319-335-6660, email@example.comADDITIONAL MEDIA CONTACTS: For Dr. Sarah Ennis and Professor Andrew Lotery, University of Southampton, UK, contact Sarah Watts, Media Relations at +44 (0) 23 8059 3807 or S.A.Watts@soton.ac.uk, A.J.Lotery@soton.ac.uk or S.Ennis@soton.ac.uk