By testing on mice, researchers from Tel Aviv University in Israel have found that congenital deafness can be caused by thyroid imbalance. The results may lead to therapeutic approaches to testing prevention of hearing loss before it occurs.
The study is unique because it tests the connection between two separate systems - the inner ear and the thyroid gland.
Hearing loss linked to disrupted thyroid hormone
The researchers tracked the hair cells of the cochlea of two groups of mice. One group, the control group, consisted of wild mice and the other of mutated congenitally deaf mice. The inner-ear hair bundles of the affected mice were labeled with bright colors to highlight their disorganization.
From this, the researchers were able to observe molecular defects consistent with disrupted thyroid hormone action or hypothyroidism in the deaf mice. Analysis of the images showed that the thyroid gland of the deaf mice grew incompletely or did not grow at all.
Still a long way
One of the researchers, Dr. Amiel Dror of Department of Human Molecular Genetics and Biochemistry at Tel Aviv’s Sackler School of Medicine, connects the two examined systems:
“Our work demonstrated that normal hearing fails to develop when thyroid hormone availability is insufficient as a result of a genetic mutation.”
He adds that the results create a platform for therapeutic approaches to prevent hearing loss before it occurs, but that there is still a long way to go before the research can contribute to the treatment of hearing impairment.
The study was published in Mammalian Genome.