Scientists have found a single gene which they believe could hold the key to age-related hearing loss. When the FGF20 gene was taken out of mice, the animals appeared perfectly healthy, but could not hear at all.
Researchers at Washington University School of Medicine found that two-thirds of the mice's outer hair cells, the delicate cells in the inner ear which amplify sounds, had disappeared.
Damage to these cells is closely associated with the development of hearing loss as a result of old age, noise exposure and some genetic conditions.
Critical for growing hair cells
The study suggests that the gene, which is also found in humans, could be critical to attempts to grow new hair cells.
The researchers removed a protein, which causes the gene to develop, while the mice were still in the womb. It is one of a number of genes which are crucial to tissue development and the healing of wounds in embryos.
Cells appeared normal
The researchers found that when the FGF20 gene was removed from mice, the animals appeared perfectly healthy, but could not hear at all. In particular, the inner hair cells, which electrically transmit the amplified sounds to the brain, appeared normal.
Lead author Dr Sung-Ho Huh said: ”?This is the first evidence that inner and outer hair cells develop independently of one another. This is important because most age-related hearing loss and noise-induced hearing loss is due to the loss of outer hair cells.'
The next step is to see whether hearing loss in humans is associated with mutations of the same gene.
Use hearing aids
Nobody can say for sure whether a medical treatment for certain types of hearing loss will be developed in the future or how expensive or complicated this treatment could be. Today, the only treatment for hearing loss is to use hearing aids and this will not change in the near future.
The study has been published in the journal PLoS Biology.