ANN ARBOR---University of Michigan scientists are part of an international team of researchers who have identified a protein that---when absent or defective because of genetic mutations---causes a disease called Usher syndrome. Children with Usher syndrome develop progressive retinal degeneration and are functionally blind by age 40. They also are born with varying degrees of hearing loss.
In an article published in the June 12 issue of Science, researchers from the University of Nebraska Medical Center, who directed the research project, reported the discovery of the gene responsible for the most common type of Usher syndrome. Collaborators Anand Swaroop, Ph.D., associate professor of ophthalmology and human genetics at the Kellogg Eye Center in the U-M Health System, and Denise Yan, Ph.D., post-doctoral fellow, are trying to learn more about the protein encoded by the Usher gene (USH2A) and its effects on the human eye.
Swaroop and Yan found large amounts of an RNA molecule, which directs production of the Usher syndrome protein, in the retina of the eye. "Since the predicted Usher protein has a physical structure similar to other extracellular matrix proteins, it may serve as the glue that holds retinal cells together," Swaroop said. "It also may provide a connecting medium for communication between different components of the retina."
In future research, U-M scientists will try to determine exactly where the USH2A protein is located in the retina and precisely what its function is. Once scientists understand what the protein does, they may be able to develop new treatments for people with Usher syndrome and other types of retinal degeneration.
The long-term implications of the study for other retinal and macular degenerations are unclear, according to Swaroop. "We do know that age-related macular degeneration---the most common cause of blindness in the elderly---is associated with changes in components of the extracellular matrix," Swaroop said. "In future research, we will try to determine if the function of the USH2A protein is altered in this disease, as well."
The research was funded by the National Institutes of Health, the Nebraska Research Initiative Fund, the Foundation Fighting Blindness and Research to Prevent Blindness.