Researchers from the Karolinska Institutet together with colleagues from the European research network TINNET recently published a study in Genetics in Medicineshowing evidence that tinnitus may have genetic causes, the Karolinska Institute announced in a press release.

Using data from the Swedish Twin Registry, researchers grouped the subjects by sex and unilateral/bilateral tinnitus, and uncovered the genetic correlation.

“We’ve been able to show that different forms of tinnitus have a significant heritability and thus a dominant genetic influence over environmental factors,” said Christopher R. Cederroth at Karolinska Institutet’s Department of Physiology and Pharmacology.

Researchers have been able to demonstrate the hereditary nature of certain forms of tinnitus. Bilateral tinnitus has been shown to depend on genetic factors, particularly in men.

Tinnitus prevalence reportedly increases with age and is thought to be related to a number of environmental factors but little research has been done on the subject. There are also no effective cures for the condition, due possibly to its heterogeneity.

“This result is surprising and unexpected as it shows that, unlike the conventional view of tinnitus being driven by environmental factors, there is a genetic influence for bilateral tinnitus which is more pronounced in men,” said Cederroth.

Their discovery also shows that bilateral and unilateral tinnitus constitute two separate sub-groups, only one of which is influenced by genetic factors. This, says Cederroth, not only has considerable clinical relevance but is also important from a public health perspective: “Tinnitus sufferers need better care and treatment than they’re currently getting. We need more genetic studies and a better molecular understanding of its generation, which could open unforeseen avenues to drug development.”

The study was financed with grants from several bodies, including the Swedish Research Council, the Lars Hierta Memorial Foundation, the Magnus Bergvall Foundation, the Silent School Foundation, and the Biomedicine and Molecular Biosciences European Cooperation in Science and Technology (COST) Action framework (TINNET, BM1306).

Original Paper:  Maas IL, Bruggemann P, Navarro TR, et al. Genetic susceptibility to bilateral tinnitus in a Swedish twin cohort. Genetics in Medicine. 2017. DOI: 10.1038/GIM.2017

Source: Karolinska Institutet, Genetics in Medicine

Image: Kheng Ho Toh |