The Antwerp team focused on a gene called TGBF1, which was already known to play a role during the development of the ear, and to be active in the otosclerotic bone.

The condition is caused by abnormal bone growth in the middle ear, which interrupts sound waves passing to the inner ear. It affects approximately 1 in 250 people.

Lead researcher Melissa Thys, from the University of Antwerp, said: "This may be a lead for better forms of treatment in the future; currently the best option is an operation. However, there is often an additional component of hearing loss which can't be restored by surgery.

SNP (single nucleotide polymorphism) analysis was used to search for genetic variations associated with otosclerosis. They found patients from Belgium and the Netherlands with otosclerosis often had a specific variant in the TGBF1 gene.

Similar results were found in a second analysis, this time of French patients.
Ms Thys said: "Combining the data from both groups gave a very significant result, from which we were able to conclude that we were the first to identify a gene that influences the weakness for otosclerosis.
"And, as further evidence, we were also able to show that a more active variant of this gene is protective against the disease."

Dr Catriona Crombie, of RNID, said: "The discovery of a gene involved in a common cause of hearing loss is a fantastic breakthrough for everyone working to improve the lives of deaf and hard of hearing people. The effects of otosclerosis can be devastating - imagine the frustration of non stop ringing in your ears, or of being constantly asked to 'speak up'. Researchers can now focus their efforts on this gene and the processes it controls to develop new ways of preventing and treating otosclerosis”

The research is published in Human Molecular Genetics (external link, opens new browser window)