Progressive hearing loss in humans and mice linked to microRNA mutation

Washington, Apr 13 (ANI): By conducting parallel studies in human and mouse, two groups of scientists have found that a new kind of gene, called a microRNA, is linked with progressive hearing loss.

MicroRNA is a tiny fragment of RNA that affects the production of hundreds of other molecules within sensory hair cells of the inner ear.

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One team, led by researchers from the Hospital Ramon y Cajal, Madrid, Spain, followed families who showed hearing loss.

The second team, led by researchers from the Wellcome Trust Sanger Institute, Cambridge, UK, examined a new line of mice, called diminuendo, that showed progressive hearing loss from an early age.

And in the end, the two groups shared their emerging data.

"We were able quite quickly to show that if the mice carried one copy of the gene variant they suffered progressive hearing loss, if they carried two variants they were profoundly deaf. The important questions were could we determine what the variant is and how does it exert its effect on hearing?" explained Professor Karen Steel, principal investigator of the programme at the Wellcome Trust Sanger Institute.

In their studies of families with progressive hearing loss, the Spanish team had suggested that the gene responsible lay on human chromosome 7.

For the study, both teams sequenced every gene in the equivalent genomic regions in human and mouse identified as implicated in hearing loss.

The sequencing showed that most of the genes in the region could not have any role to play in hearing loss.

However, each of the team found that a mutation in a microRNA gene called miR-96 was associated with the hearing loss.

"We know of a number of genes involved in deafness in humans and mice but, to our great surprise, this was one of a new class of genes called microRNAs," explained Professor Miguel Angel Moreno-Pelayo, senior author on the human study.

Understanding the mechanism by which miR-96 leads to progressive hearing loss could provide clues to help develop therapies to improve the effects of progressive deafness, regardless of the trigger. (ANI)