Hearing Loss Gene Discovered
October 1, 2012

New Gene Associated With Hearing Loss Discovered

redOrbit Staff & Wire Reports - Your Universe Online

A team of researchers, led by members of the University of Cincinnati (UC) and Cincinnati Children's Hospital Medical Center, have reportedly discovered a new genetic mutation that leads to deafness and hearing loss associated with a relatively rare condition.

In a September 30 press release, lead investigator and UC assistant professor of ophthalmology Zubair Ahmed explain that he and his colleagues were "able to pinpoint the gene which caused deafness in Usher syndrome type 1 as well as deafness that is not associated with the syndrome through the genetic analysis of 57 humans from Pakistan and Turkey."

The culprit, according to Ahmed, is a protein known as CIB2. Mutations in the protein, which binds to calcium inside cells, has been discovered to be linked to deafness both in Usher syndrome and cases of non-syndromic hearing loss.

He noted that these mutations were found to be the primary genetic cause of non-syndromic hearing loss in Pakistan, and that during their research, he and his colleagues discovered a second CIB2 mutation that has been linked to deafness among people of Turkish heritage.

"In animal models, CIB2 is found in the mechanosensory stereocilia of the inner ear -- hair cells, which respond to fluid motion and allow hearing and balance, and in retinal photoreceptor cells, which convert light into electrical signals in the eye, making it possible to see," Saima Riazuddin, assistant professor in UC's department of otolaryngology and co-lead investigator on the study, added in a statement.

Ahmed, Riazuddin, and company found that CIB2 tended to be stained brighter at the tips of shorter rows of the cellular apical modifications known as stereocilia than nearby longer rows, where it could be involved in the calcium signaling process which regulates how the ear converts mechanical energy into the type of energy recognizable by a person's brain as sound.

"With this knowledge, we are one step closer to understanding the mechanism of mechano-electrical transduction and possibly finding a genetic target to prevent non-syndromic deafness as well as that associated with Usher syndrome type 1," Ahmed explained.

Their work appears in the Sept. 30 advance online edition of the journal Nature Genetics. Researchers from the National Institute on Deafness and other Communication Disorders (NIDCD), the Baylor College of Medicine and the University of Kentucky were also involved in the study, which was funded by the NIDCD, the National Science Foundation (NSF), and the Research to Prevent Blindness Foundation.