One variant protects the ear, while the other induces otosclerosis.
Researchers from the University of Antwerp, Belgium, discovered that mutations in the gene TGBF1 are responsible for otosclerosis, the single most common cause of hearing loss among white adults.
“The gene in which the variant is located points to a pathway that contributes to the disease,” notes Melissa Thys, from the Department of Medical Genetics. “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 that can’t be restored by surgery. As the gene involved is a growth factor and the disease manifests itself by the abnormal growth of bone in the middle ear, it may have a large potential for therapy.”
The researchers studied TGBF1, which they already knew had nongenetic indications of involvement in otosclerosis. It plays a role during embryonic development of the ear and is expressed in otosclerotic bone. They used SNP analysis to study a large patient and control population from Belgium and The Netherlands. The team found significant results for an amino acid changing SNP in TGBF1. Analysis of a large French group showed the same association.
“Combining the data from both groups with a common odds ratio gave a significant result from which we were able to conclude that we were the first to identify a gene that influences the susceptibility for otosclerosis,” reports Thys. “And, as further evidence, we were also able to show that a more active variant of this gene is protective against the disease.”
The research was reported at the annual conference of the European Society of Human Genetics.