University of Oulu

Kraatari-Tiri M, Haanpää MK, Willberg T, Pohjola P, Keski-Filppula R, Kuismin O, Moilanen JS, Häkli S, Rahikkala E. Clinical and Genetic Characteristics of Finnish Patients with Autosomal Recessive and Dominant Non-Syndromic Hearing Loss Due to Pathogenic TMC1 Variants. Journal of Clinical Medicine. 2022; 11(7):1837.

Clinical and genetic characteristics of Finnish patients with autosomal recessive and dominant non-syndromic hearing loss due to pathogenic TMC1 variants

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Author: Kraatari-Tiri, Minna1,2; Haanpää, Maria K.3,4; Willberg, Tytti5;
Organizations: 1Department of Clinical Genetics, Oulu University Hospital, 90029 Oulu, Finland
2PEDEGO Research Unit, Medical Research Center Oulu, Oulu University Hospital, and University of Oulu, 90014 Oulu, Finland
3Department of Clinical Genetics, Turku University Hospital, 20521 Turku, Finland
4Department of Genomics, Turku University Hospital, 20521 Turku, Finland
5Department of Otorhinolaryngology, Turku University Hospital, 20521 Turku, Finland
6Department of Otorhinolaryngology, Oulu University Hospital, 90029 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.9 MB)
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Language: English
Published: Multidisciplinary Digital Publishing Institute, 2022
Publish Date: 2022-09-15


Sensorineural hearing loss (SNHL) is one of the most common sensory deficits worldwide, and genetic factors contribute to at least 50–60% of the congenital hearing loss cases. The transmembrane channel-like protein 1 (TMC1) gene has been linked to autosomal recessive (DFNB7/11) and autosomal dominant (DFNA36) non-syndromic hearing loss, and it is a relatively common genetic cause of SNHL. Here, we report eight Finnish families with 11 affected family members with either recessively inherited homozygous or compound heterozygous TMC1 variants associated with congenital moderate-to-profound hearing loss, or a dominantly inherited heterozygous TMC1 variant associated with postlingual progressive hearing loss. We show that the TMC1 c.1534C>T, p.(Arg512*) variant is likely a founder variant that is enriched in the Finnish population. We describe a novel recessive disease-causing TMC1 c.968A>G, p.(Tyr323Cys) variant. We also show that individuals in this cohort who were diagnosed early and received timely hearing rehabilitation with hearing aids and cochlear implants (CI) have reached good speech perception in noise. Comparison of the genetic data with the outcome of CI rehabilitation increases our understanding of the extent to which underlying pathogenic gene variants explain the differences in CI rehabilitation outcomes.

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Series: Journal of clinical medicine
ISSN: 2077-0383
ISSN-E: 2077-0383
ISSN-L: 2077-0383
Volume: 11
Issue: 7
Article number: 1837
DOI: 10.3390/jcm11071837
Type of Publication: A1 Journal article – refereed
Field of Science: 3125 Otorhinolaryngology, ophthalmology
Funding: This study was funded by Academy of Finland (grant number 338446), Uolevi Mäki Foundation, and the Competitive State Research Financing of the Expert Responsibility Area of Oulu University Hospital (grant number VTR K36733).
Academy of Finland Grant Number: 338446
Detailed Information: 338446 (Academy of Finland Funding decision)
Copyright information: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (