London, Oct 12 (PTI) Scientists have discovered 52previously unidentified genes critical for hearing by testingover 3,000 mouse genes, an advance that will provide insightsinto the causes of hearing loss in humans.
The study, published in the journal NatureCommunications, tested 3,006 strains of 'knock-out' mice forsigns of hearing loss.
'Knock-out' mice have one gene from their genomeinactivated, which helps researchers to uncover the functionsof that gene.
"Importantly, the large number of hearing loss genesidentified in this study demonstrates that there are manymore genes involved in deafness in mouse and human genomesthan we had previously realised," said Steve Brown, Directorof Medical Research Council (MRC) Harwell in the UK.
The hearing thresholds of the knock-out mice wereassessed with rising volumes of sound at five differentfrequencies - mice were considered hearing impaired if theycould not hear the quieter sounds for two or morefrequencies.
They identified 67 genes that were associated withhearing loss, of which 52 had not been previously linked withhearing loss.
The genes identified varied in how they affected hearing- effects ranged from mild to severe hearing loss or resultedin difficulties at lower or higher frequencies.
The knock-out mice tested in the study represented onlyabout 15 per cent of mouse genes, so the researchers estimatethat if the entire genome is searched there will be at least450 genes required for hearing function.
In humans, there are over 400 genetic syndromes thatinclude a hearing loss component, however most of the genesunderlying hearing loss syndromes are currently unknown.
"Our findings identify 52 genes that have previously notbeen recognised as being critical for hearing," said Brown.
"These increase our knowledge of the many genes andmolecular mechanisms required for hearing, and also provide ashortlist of new genes to investigate to discover the geneticbasis of many human hearing loss syndromes.
"Testing these genes in people with hearing loss may helpto improve diagnosis and counselling of patients," he said.
PTI SARSAR.
This is unedited, unformatted feed from the Press Trust of India wire.