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A biallelic variant in CLRN2 causes non-syndromic hearing loss in humans
Journal article   Open access   Peer reviewed

A biallelic variant in CLRN2 causes non-syndromic hearing loss in humans

Barbara Vona, Neda Mazaheri, Sheng-Jia Lin, Lucy A Dunbar, Reza Maroofian, Hela Azaiez, Kevin T Booth, Sandrine Vitry, Aboulfazl Rad, Franz Rüschendorf, …
Human genetics, Vol.140(6), pp.915-931
06/2021
DOI: 10.1007/s00439-020-02254-z
PMCID: PMC8099798
PMID: 33496845
url
https://doi.org/10.1007/s00439-020-02254-zView
Published (Version of record) Open Access

Abstract

Deafness, the most frequent sensory deficit in humans, is extremely heterogeneous with hundreds of genes involved. Clinical and genetic analyses of an extended consanguineous family with pre-lingual, moderate-to-profound autosomal recessive sensorineural hearing loss, allowed us to identify CLRN2, encoding a tetraspan protein, as a new deafness gene. Homozygosity mapping followed by exome sequencing identified a 14.96 Mb locus on chromosome 4p15.32p15.1 containing a likely pathogenic missense variant in CLRN2 (c.494C > A, NM_001079827.2) segregating with the disease. Using in vitro RNA splicing analysis, we show that the CLRN2 c.494C > A variant leads to two events: (1) the substitution of a highly conserved threonine (uncharged amino acid) to lysine (charged amino acid) at position 165, p.(Thr165Lys), and (2) aberrant splicing, with the retention of intron 2 resulting in a stop codon after 26 additional amino acids, p.(Gly146Lysfs*26). Expression studies and phenotyping of newly produced zebrafish and mouse models deficient for clarin 2 further confirm that clarin 2, expressed in the inner ear hair cells, is essential for normal organization and maintenance of the auditory hair bundles, and for hearing function. Together, our findings identify CLRN2 as a new deafness gene, which will impact future diagnosis and treatment for deaf patients.
Adult Alleles Amino Acid Substitution Animals Base Sequence Chromosome Mapping Chromosomes, Human, Pair 4 - chemistry Consanguinity Female Gene Expression Genes, Recessive Hair Cells, Auditory, Inner - metabolism Hair Cells, Auditory, Inner - pathology Hearing Loss, Sensorineural - genetics Hearing Loss, Sensorineural - metabolism Hearing Loss, Sensorineural - pathology Humans Male Membrane Proteins - deficiency Membrane Proteins - genetics Mice Pedigree Point Mutation Whole Exome Sequencing Zebrafish

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