- Email: [email protected]
A nonsynonymous mutation in the WFS1 gene in a Finnish family with age-related hearing impairment
Hearing Research xxx (2017) 1e5
Contents lists available at ScienceDirect
Hearing Research journal homepage: www.elsevier.com/locate/heares
Short communication
A nonsynonymous mutation in the WFS1 gene in a Finnish family with age-related hearing impairment € vuori a, b, c, *, Samuli Hannula a, d, e, Elina Ma €ki-Torkko d, f, g, Martti Sorri a, d, e, Laura Kyto Kari Majamaa a, b, c a
Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland Research Unit of Clinical Neuroscience, University of Oulu, P.O. Box 5000, FI-90014 Oulu, Finland Department of Neurology, Oulu University Hospital, P.O. Box 20, FI-90029 Oulu, Finland d Department of Otorhinolaryngology and Head and Neck Surgery, Oulu University Hospital, P.O. Box 21, FI-90029 Oulu, Finland e PEDEGO Research Unit, University of Oulu, P.O. Box 5000, FI-90014 Oulu, Finland f €ping University, S-581 85 Linko €ping, Sweden Department of Clinical and Experimental Medicine/Technical Audiology, Faculty of Health Sciences, Linko g € €tland, Sweden Department of ENT-Head Neck Surgery, Region Osterg o b c
a r t i c l e i n f o
a b s t r a c t
Article history: Received 7 September 2016 Received in revised form 12 March 2017 Accepted 23 September 2017 Available online xxx
Wolfram syndrome (WS) is caused by recessive mutations in the Wolfram syndrome 1 (WFS1) gene. Sensorineural hearing impairment (HI) is a frequent feature in WS and, furthermore, certain mutations in WFS1 cause nonsyndromic dominantly inherited low-frequency sensorineural HI. These two phenotypes are clinically distinct indicating that WFS1 is a reasonable candidate for genetic studies in patients with other phenotypes of HI. Here we have investigated, whether the variation in WFS1 has a pathogenic role in age-related hearing impairment (ARHI). WFS1 gene was investigated in a population sample of 518 Finnish adults born in 1938e1949 and representing variable hearing phenotypes. Identified variants were evaluated with respect to pathogenic potential. A rare mutation predicted to be pathogenic was found in a family with many members with impaired hearing. Twenty members were recruited to a segregation study and a detailed clinical examination. Heterozygous p.Tyr528His variant segregated completely with late-onset HI in which hearing deteriorated first at high frequencies and progressed to mid and low frequencies later in life. We report the first mutation in the WFS1 gene causing late-onset HI with audiogram configurations typical for ARHI. Monogenic forms of ARHI are rare and our results add WFS1 to the short list of such genes. © 2017 Elsevier B.V. All rights reserved.
Keywords: Age-related hearing impairment Presbyacusis Wolfram syndrome High-frequency hearing impairment
1. Introduction Wolfram syndrome (WS [MIM: 222300]) is a rare autosomal recessive disorder that is caused by mutations in the Wolfram Syndrome 1 (WFS1) gene (Wolfram and Wagener, 1938; Inoue et al., 1998). Patients with WS commonly have bilateral sensorineural hearing impairment (HI) affecting high frequencies, and their heterozygous family members have an increased risk of HI as well (Barrett et al., 1995; Ohata et al., 1998). Certain mutations in WFS1
Abbreviations: ARHI, age-related hearing impairment; BEHL, better ear hearing level; HI, hearing impairment; WFS1, Wolfram Syndrome 1; WS, Wolfram syndrome; LFSNHI, low-frequency sensorineural hearing impairment * Corresponding author. Research Unit of Clinical Neuroscience, University of Oulu, P.O. Box 5000, FI-90014 Oulu, Finland. € vuori). E-mail address: laura.kytovuori@oulu.fi (L. Kyto
also cause non-syndromic autosomal dominant low-frequency sensorineural hearing impairment (LFSNHI [MIM: 600965]) (Bespalova et al., 2001; Young et al., 2001). Age-related HI (ARHI) is a common type of adult-onset HI. The prevalence of ARHI has been reported to be 36.8% among men aged 54e66 years and 18.4% among women in Finland (Hannula et al., 2010). ARHI typically manifests with an audiogram configuration showing sloping at higher frequencies (Hannula et al., 2011). The genetic etiology of the trait is complex. A recent large-scale genome-wide association study has failed to replicate any of the previous associations indicating a polygenic nature of ARHI (Fransen et al., 2014). ARHI has been successfully modeled in mice, but corresponding genes in humans rarely cause late-onset HI (Johnson et al., 1997; Bork et al., 2001; Yan et al., 2013). Only few monogenic forms of HI resembling ARHI have been reported in the literature (Walsh et al., 2010; Oonk et al., 2013). The aim of the
https://doi.org/10.1016/j.heares.2017.09.013 0378-5955/© 2017 Elsevier B.V. All rights reserved.
€vuori, L., et al., A nonsynonymous mutation in the WFS1 gene in a Finnish family with age-related hearing Please cite this article in press as: Kyto impairment, Hearing Research (2017), https://doi.org/10.1016/j.heares.2017.09.013
€vuori et al. / Hearing Research xxx (2017) 1e5 L. Kyto
2
present study was to investigate, if the rare variants in WFS1 could be involved in the development of ARHI in Finnish subjects. 2. Subjects and methods The subjects (N ¼ 518) were randomly sampled from the population register in 2003 and it was required that the subjects were born in 1938e1949 and that they resided in the city of Oulu or in the surrounding areas (Hannula et al., 2010). Otological examination was performed by an ENT specialist at an office visit and their otological and audiological history was reviewed in a structured interview that was based on a previsit questionnaire. Pure tone audiometry was conducted according to ISO 8253-1 (1989) standard. HI was defined as better ear hearing level over the frequencies 0.5, 1, 2 and 4 kHz (BEHL0.5, 1, 2, 4 kHz) 20 dB HL (Stephens, 1996). The asymmetric or conductive HI was defined as previously (Hannula et al., 2010). For further analyses the subjects were divided in subgroups according to high-frequency HI (BEHL4, 6, 8 kHz 30 dB HL) and low-frequency HI (BEHL0.125, 0.25, 0.5 kHz 15 dB HL). The controls consisted of subjects who had BEHL0.5, 1, 2, 4 kHz < 20 dB, BEHL4, 6, 8 kHz < 20 dB, and BEHL0.125, 0.25, 0.5 kHz < 15 dB HL. History of noise exposure was screened with questions on exposure to occupational noise, leisure time noise and gunfire noise. The study protocol was approved by National Committee on Medical Research Ethics. All subjects gave their written informed consent. Amplification of WFS1 exon 8 was performed in three overlapping fragments using Phire Hot Start II DNA polymerase (Thermo Fisher Scientific, Waltham, MA, U.S.A.) in 280 subjects with HI fulfilling the aforementioned definitions. Sequencing was carried out using BigDyeTerminator v1.1 cycle sequencing kit (Applied Biosystems™, Thermo Fisher Scientific) and 3500xL Genetic Analyzer at Biocenter Oulu sequencing core facility. The discovered variants were evaluated using a consensus classifier PredictSNP (Bendl et al., 2014). Family history was examined for further selection of the patients. The carrier of the one putatively pathogenic variant reported high prevalence of HI among her family members. Therefore, all family members older than 40 years were invited to a segregation analysis and clinical examination that were performed in 2015 and that included the proband, her child and her eight siblings and 11 children of the siblings. 3. Results Hearing impairment (BEHL0.5, 1, 2, 4 kHz 20 dB HL) was diagnosed in 112 subjects. Moreover, high frequencies were affected (BEHL4, 6, 8 kHz 30 dB HL) in 255 subjects, and a pure highfrequency HI was found in 149 subjects. Among the subjects we discovered seven variants that were then evaluated as a possible cause of HI. Five of these variants were predicted to be deleterious (Table 1). The audiogram configurations of the five carriers were sloping at the high frequencies. The c.1582T > C transition (p.Tyr528His) was found in a woman (II-6), who reported several members with HI in her family (Fig. 1). The p.Tyr528His mutation was predicted to be pathogenic in silico, and it has been found once in 120,122 alleles in ExAC database (rs761976067; http://exac. broadinstitute.org, accessed in January 2017). The proband had mild ARHI (BEHL0.5, 1, 2, 4 kHz 38 dB HL) at the age of 65 years. The second clinical examination at the age of 76 years revealed progression of the HI (BEHL0.5, 1, 2, 4 kHz 48 dB HL). Review of the patient's charts showed that she had had a mild HI at high frequencies (BEHL4, 6, 8 kHz 28 dB HL) in her first audiogram at the age of 45 years (Fig. 2). Otological and audiological risk factors for HI were enquired from all family members. The most common risk factor for HI was
noise exposure. All men and two women reported some exposure to noise. None of the subjects had a history of ototoxic medication, or central nervous system infection. In addition, none of the subjects had optic atrophy. Clinical otological examination did not reveal abnormalities. Four subjects reported onset of HI between 15 and 40 years of age and 16 subjects at 40 years of age and all of them reported slow progression of HI. One mutation carrier had an asymmetric HI but, as magnetic resonance imaging did not reveal retrocochlear pathology, his better ear was included in the analyses. A daughter of II-7 was excluded from the analyses on the basis of a mixed HI in the right ear and high-frequency sensorineural HI on the left. She did not carry p.Tyr528His or any other putatively pathogenic mutations in the WFS1 gene. The audiogram configuration on the left was atypical, as it partly resembled a U-shaped one combined with a deep dip in the two highest frequencies. Such a finding is not typical for ARHI. The remaining subjects had symmetric sensorineural HI in audiograms. BEHL was worse in subjects with p.Tyr528His than in those with the homozygous wild-type variant (Fig. 1B). The mean difference was 8e15 dB at frequencies 0.125, 0.250, 0.5 and 1 kHz among subjects in generation II, while the mean hearing levels were similar at frequencies 2, 4, 6 and 8 kHz. In generation III the subjects with wild-type genotype had a minor drop in the audiogram within the highest frequencies. However, III-4 harboring the mutation had an explicit steeply sloping audiogram configuration and sensorineural HI in both ears. His BEHL0.5, 1, 2, 4 kHz was 35 dB at the age of 57 years. Moreover, his first hearing tests had already revealed high-frequency HI (BEHL4, 6, 8 kHz 48 dB) at the age of 45 years, which had progressed to the present level of 77 dB HL. For the comparison, his male cousin (III-9) with the worst hearing had HL of 13 dB and 43 dB at the age of 53 years with respect to the mid and high frequencies. 4. Discussion We found that p.Tyr528His was pathogenic in silico and that it segregated with late-onset HI clinically resembling ARHI. Interestingly, homozygous p.Tyr528Asp mutation has been found in two unrelated patients with WS and HI (Zalloua et al., 2008; Aloi et al., 2012). Furthermore, a homozygous nonsense mutation p.Tyr528* has been detected in a boy with WS and HI (Colosimo et al., 2003) suggesting that the nucleotides in the codon of amino acid residue 528 are vulnerable for mutations. A systematic review has shown that 48% of WS patients manifest HI with a median onset-age of 14 years (de Heredia et al., 2013). WFS1-accociated dominantly inherited LFSNHI is a clinical entity characterized by an ascending audiogram configuration. The age of onset of LFSNHI varies, but usually HI has been noted by the end of the second decade (Young et al., 2001; Lesperance et al., 2003; Fukuoka et al., 2007). HI is progressive, but a rather stereotypic audiogram configuration is recognizable even in the eldest family members (Lesperance et al., 2003; Pennings et al., 2003). The mutation carriers in our family had high-frequency sloping audiograms consistent with the most prevalent audiogram configuration in ARHI (Hannula et al., 2011). Moreover, the audiogram configurations did not resemble WFS1-related LFSNHI at any age (Fig. 2). Almost all Finnish men have at least some exposure to gunfire noise owing to mandatory military service and hunting as a popular leisure time activity. Indeed, all the men in the family reported a history of some noise exposure. Unfortunately, there was only one mutation carrier among the three descendants of the mutation carriers. Studies among the fourth generation and findings in an independent family will be required to confirm the association of
€ vuori, L., et al., A nonsynonymous mutation in the WFS1 gene in a Finnish family with age-related hearing Please cite this article in press as: Kyto impairment, Hearing Research (2017), https://doi.org/10.1016/j.heares.2017.09.013
€vuori et al. / Hearing Research xxx (2017) 1e5 L. Kyto
3
Table 1 Five rare variants in WFS1 that were evaluated as a possible cause of HI in Finnish subjects with variable hearing phenotypes. Alleles in ExACa Nucleotide change
Amino acid change
All populations
Finland
Controlsb (N ¼ 149)
PredictSNPc (Confidence)
Type of HId
Previous findings
c.1209G > T
p.Glu403Asp
8
5
0
Deleterious (61%)
High
c.1582T > C
p.Tyr528His
1
0
0
Deleterious (72%)
Mid and High
Found in patients with HI and €vuori et al., 2013) DM (Kyto p.Tyr528Asp and p.Tyr528* are pathogenic WS mutations (Colosimo et al., 2003; Zalloua et al., 2008; Aloi et al., 2012)
c.1976T > G c.2026C > T c.2084G > A
p.Val659Gly p.Arg676Cys p.Gly695Asp
0 10 6
0 0 2
0 0 1
Deleterious (51%) Deleterious (61%) Deleterious (87%)
High High Mid and High
a b c d
p.Gly695Val is pathogenic WS mutation (Inoue et al., 1998)
ExAC database, http://exac.broadinstitute.org, total N (all populations) > 120,000, total N (Finland) > 6500. Subjects who had BEHL0.5, 1,2, 4 kHz < 20 dB, BEHL4, 6, 8 kHz < 20 dB, and BEHL0.125, 0.25, 0.5 kHz < 15 dB HL. Bendl et al., 2014. High, BEHL 4, 6, 8 kHz 30 dB, Mid, BEHL 0.5, 1, 2, 4 kHz 20 dB.
the WFS1 in ARHI. Interestingly, it has been suggested that an impairment in the unfolded protein response (UPR) is involved in the pathomechanism of ARHI (Wang et al., 2015) and that the wolframin protein participates in the signaling pathway of UPR
(Fonseca et al., 2005). When the incidence of a trait is age-related, the contribution of rare variants may be difficult to estimate while the phenotype can be still undeveloped. A recent study supports polygenic nature of
Fig. 1. Segregation of the heterozygous p.Tyr528His variant in a Finnish family. (A) Pedigree of the family. Arrow, proband; open circle, asymptomatic female; open square, asymptomatic male; dark gray circle, female with hearing impairment (HI) and with p.Tyr528His; dark gray square, male with HI and with p.Tyr528His; light gray circle, female with HI; light gray square, male with HI; ,-, carrier of p.Tyr528His; ,,, wild type. Ages are shown under the genotype symbol. (B) Audiograms of the family members in different generations. Carriers of p.Tyr528His and subjects with wild type genotype are presented separately in each generation.
€vuori, L., et al., A nonsynonymous mutation in the WFS1 gene in a Finnish family with age-related hearing Please cite this article in press as: Kyto impairment, Hearing Research (2017), https://doi.org/10.1016/j.heares.2017.09.013
€vuori et al. / Hearing Research xxx (2017) 1e5 L. Kyto
4
Fig. 2. Progression of HI in the family with p.Tyr528His in the WFS1 gene. Audiograms represent better ear hearing thresholds of five subjects harboring the p.Tyr528His variant and two subjects with the wild type (WT) genotype. The ages are shown on the right side of each panel.
ARHI and suggests that there are no major causative genes (Fransen et al., 2014). For future investigations, we strongly recommend the use of families with high prevalence of late-onset HI. ARHI has not been investigated with the same intensity as HI in children, even though the prevalence of ARHI outnumbers several-fold that of HI in children. Improved genetic diagnostics could bring the younger generation into clinical examinations earlier. To conclude, our findings show that mutations in WFS1 play a role in age-related HI in addition to WS-related HI and dominantly inherited HI affecting low frequencies. Conflict of interest, and author contributions €vuori designed The authors declare no conflict of interest. L. Kyto the study, did the molecular investigations, and wrote the first draft. S. Hannula collected the samples and did the clinical exam€ki-Torkko, and M. Sorri supervised the clinical study. inations. E. Ma K. Majamaa designed the study and supervised the project. All authors revised the manuscript. All authors have approved the final manuscript. Acknowledgements The authors acknowledge the technical assistance of Ms. Anja Heikkinen. The study was supported by grants from the Sigrid Juselius Foundation, Medical Research Center, University of Oulu and Oulu University Hospital, and State research funding from Oulu University Hospital. The sponsors have not been involved in designing or conduction of this study. References Aloi, C., Salina, A., Pasquali, L., Lugani, F., Perri, K., Russo, C., Tallone, R., Ghiggeri, G.M., Lorini, R., d'Annunzio, G., 2012. Wolfram syndrome: new
mutations, different phenotype. PLoS One 7, e29150. Barrett, T.G., Bundey, S.E., Macleod, A.F., 1995. Neurodegeneration and diabetes: UK nationwide study of wolfram (DIDMOAD) syndrome. Lancet 346, 1458e1463. Bendl, J., Stourac, J., Salanda, O., Pavelka, A., Wieben, E.D., Zendulka, J., Brezovsky, J., Damborsky, J., 2014. PredictSNP: robust and accurate consensus classifier for prediction of disease-related mutations. PLoS Comput. Biol. 10 e1003440. Bespalova, I.N., Van Camp, G., Bom, S.J., Brown, D.J., Cryns, K., DeWan, A.T., Erson, A.E., Flothmann, K., Kunst, H.P., Kurnool, P., Sivakumaran, T.A., Cremers, C.W., Leal, S.M., Burmeister, M., Lesperance, M.M., 2001. Mutations in the wolfram syndrome 1 gene (WFS1) are a common cause of low frequency sensorineural hearing loss. Hum. Mol. Genet. 10, 2501e2508. Bork, J.M., Peters, L.M., Riazuddin, S., Bernstein, S.L., Ahmed, Z.M., Ness, S.L., Polomeno, R., Ramesh, A., Schloss, M., Srisailpathy, C.R., Wayne, S., Bellman, S., Desmukh, D., Ahmed, Z., Khan, S.N., Kaloustian, V.M., Li, X.C., Lalwani, A., Riazuddin, S., Bitner-Glindzicz, M., Nance, W.E., Liu, X.Z., Wistow, G., Smith, R.J., Griffith, A.J., Wilcox, E.R., Friedman, T.B., Morell, R.J., 2001. Usher syndrome 1D and nonsyndromic autosomal recessive deafness DFNB12 are caused by allelic mutations of the novel cadherin-like gene CDH23. Am. J. Hum. Genet. 68, 26e37. Colosimo, A., Guida, V., Rigoli, L., Di Bella, C., De Luca, A., Briuglia, S., Stuppia, L., Salpietro, D.C., Dallapiccola, B., 2003. Molecular detection of novel WFS1 mutations in patients with wolfram syndrome by a DHPLC-based assay. Hum. Mutat. 21, 622e629. ries, R., Nunes, V., 2013. Genotypic classification of patients de Heredia, M.L., Cle with Wolfram syndrome: insights into the natural history of the disease and correlation with phenotype. Genet. Med. 15, 497e506. Fonseca, S.G., Fukuma, M., Lipson, K.L., Nguyen, L.X., Allen, J.R., Oka, Y., Urano, F., 2005. WFS1 is a novel component of the unfolded protein response and maintains homeostasis of the endoplasmic reticulum in pancreatic beta-cells. J. Biol. Chem. 280, 39609e39615. Fransen, E., Bonneux, S., Corneveaux, J.J., Schrauwen, I., Di Berardino, F., White, C.H., Ohmen, J.D., Van de Heyning, P., Ambrosetti, U., Huentelman, M.J., Van Camp, G., Friedman, R.A., 2014. Genome-wide association analysis demonstrates the highly polygenic character of age-related hearing impairment. Eur. J. Hum. Genet. 23, 110e115. Fukuoka, H., Kanda, Y., Ohta, S., Usami, S.I., 2007. Mutations in the WFS1 gene are a frequent cause of autosomal dominant nonsyndromic low-frequency hearing loss in Japanese. J. Hum. Genet. 52, 510e515. Hannula, S., M€ aki-Torkko, E., Majamaa, K., Sorri, M., 2010. Hearing in a 54- to 66year-old population in northern Finland. Int. J. Audiol. 49, 920e927. €ki-Torkko, E., 2011. Audiogram Hannula, S., Bloigu, R., Majamaa, K., Sorri, M., Ma configurations among older adults: prevalence and relation to self-reported hearing problems. Int. J. Audiol. 50, 793e801. Inoue, H., Tanizawa, Y., Wasson, J., Behn, P., Kalidas, K., Bernal-Mizrachi, E.,
€ vuori, L., et al., A nonsynonymous mutation in the WFS1 gene in a Finnish family with age-related hearing Please cite this article in press as: Kyto impairment, Hearing Research (2017), https://doi.org/10.1016/j.heares.2017.09.013
€vuori et al. / Hearing Research xxx (2017) 1e5 L. Kyto Mueckler, M., Marshall, H., Donis-Keller, H., Crock, P., Rogers, D., Mikuni, M., Kumashiro, H., Higashi, K., Sobue, G., Oka, Y., Permutt, M.A., 1998. A gene encoding a transmembrane protein is mutated in patients with diabetes mellitus and optic atrophy (wolfram syndrome). Nat. Genet. 20, 143e148. Johnson, K.R., Erway, L.C., Cook, S.A., Willott, J.F., Zheng, Q.Y., 1997. A major gene affecting age-related hearing loss in C57BL/6J mice. Hear. Res. 114, 83e92. €vuori, L., Seppa €nen, A., Martikainen, M.H., Moilanen, J.S., Kamppari, S., Kyto €nen, P., Ro € nnemaa, T., Majamaa, K., 2013. WFS1 S€ arkioja, T., Remes, A.M., R€ asa variants in Finnish patients with diabetes mellitus, sensorineural hearing impairment or optic atrophy, and in suicide victims. J. Hum. Genet. 58, 495e500. Lesperance, M.M., Hall, J.W., San Agustin, T.B., Leal, S.M., 2003. Mutations in the Wolfram syndrome type 1 gene (WFS1) define a clinical entity of dominant lowfrequency sensorineural hearing loss. Arch. Otolaryngol. Head Neck Surg. 129, 411e420. Ohata, T., Koizumi, A., Kayo, T., Shoji, Y., Watanabe, A., Monoh, K., Higashi, K., Ito, S., Ogawa, O., Wada, Y., Takada, G., 1998. Evidence of an increased risk of hearing loss in heterozygous carriers in a wolfram syndrome family. Hum. Genet. 103, 470e474. Oonk, A.M., Leijendeckers, J.M., Lammers, E.M., Weegerink, N.J., Oostrik, J., Beynon, A.J., Huygen, P.L., Kunst, H.P., Kremer, H., Snik, A.F., Pennings, R.J., 2013. Progressive hereditary hearing impairment caused by a MYO6 mutation resembles presbyacusis. Hear. Res. 299, 88e98. Pennings, R.J., Bom, S.J., Cryns, K., Flothmann, K., Huygen, P.L., Kremer, H., Van Camp, G., Cremers, C.W., 2003. Progression of low-frequency sensorineural hearing loss (DFNA6/14-WFS1). Arch. Otolaryngol. Head Neck Surg. 129, 421e426. Stephens, D., 1996. Study Group on Terminology, Definitions and Hearing Assessment. European Work Group on Genetics of Hearing Impairment. European Commission Directorate, Biomedical and Health Research Program (HEAR) Info letter, 2.
5
Walsh, T., Pierce, S.B., Lenz, D.R., Brownstein, Z., Dagan-Rosenfeld, O., Shahin, H., Roeb, W., McCarthy, S., Nord, A.S., Gordon, C.R., Ben-Neriah, Z., Sebat, J., Kanaan, M., Lee, M.K., Frydman, M., King, M.C., Avraham, K.B., 2010. Genomic duplication and overexpression of TJP2/ZO-2 leads to altered expression of apoptosis genes in progressive nonsyndromic hearing loss DFNA51. Am. J. Hum. Genet. 87, 101e109. Wang, W., Sun, Y., Chen, S., Zhou, X., Wu, X., Kong, W., Kong, W., 2015. Impaired unfolded protein response in the degeneration of cochlea cells in a mouse model of age-related hearing loss. Exp. Gerontol. 70, 61e70. Wolfram, D.J., Wagener, H.P., 1938. Diabetes mellitus and simple optic atrophy among siblings: report of four cases. Mayo Clin. Proc. 13, 715e718. Yan, D., Zhu, Y., Walsh, T., Xie, D., Yuan, H., Sirmaci, A., Fujikawa, T., Wong, A.C., Loh, T.L., Du, L., Grati, M., Vlajkovic, S.M., Blanton, S., Ryan, A.F., Chen, Z.Y., Thorne, P.R., Kachar, B., Tekin, M., Zhao, H.B., Housley, G.D., King, M.C., Liu, X.Z., 2013. Mutation of the ATP-gated P2X(2) receptor leads to progressive hearing loss and increased susceptibility to noise. Proc. Natl. Acad. Sci. U. S. A. 110, 2228e2233. Young, T.L., Ives, E., Lynch, E., Person, R., Snook, S., MacLaren, L., Cater, T., Griffin, A., Fernandez, B., Lee, M.K., King, M.C., 2001. Non-syndromic progressive hearing loss DFNA38 is caused by heterozygous missense mutation in the wolfram syndrome gene WFS1. Hum. Mol. Genet. 10, 2509e2514. Zalloua, P.A., Azar, S.T., Delepine, M., Makhoul, N.J., Blanc, H., Sanyoura, M., Lavergne, A., Stankov, K., Lemainque, A., Baz, P., Julier, C., 2008. WFS1 mutations are frequent monogenic causes of juvenile-onset diabetes mellitus in Lebanon. Hum. Mol. Genet. 17, 4012e4021.
Web resources ExAC database, http://exac.broadinstitute.org. Nature, https://doi.org/10.1038/ nature19057.
€vuori, L., et al., A nonsynonymous mutation in the WFS1 gene in a Finnish family with age-related hearing Please cite this article in press as: Kyto impairment, Hearing Research (2017), https://doi.org/10.1016/j.heares.2017.09.013
Contents lists available at ScienceDirect
Hearing Research journal homepage: www.elsevier.com/locate/heares
Short communication
A nonsynonymous mutation in the WFS1 gene in a Finnish family with age-related hearing impairment € vuori a, b, c, *, Samuli Hannula a, d, e, Elina Ma €ki-Torkko d, f, g, Martti Sorri a, d, e, Laura Kyto Kari Majamaa a, b, c a
Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland Research Unit of Clinical Neuroscience, University of Oulu, P.O. Box 5000, FI-90014 Oulu, Finland Department of Neurology, Oulu University Hospital, P.O. Box 20, FI-90029 Oulu, Finland d Department of Otorhinolaryngology and Head and Neck Surgery, Oulu University Hospital, P.O. Box 21, FI-90029 Oulu, Finland e PEDEGO Research Unit, University of Oulu, P.O. Box 5000, FI-90014 Oulu, Finland f €ping University, S-581 85 Linko €ping, Sweden Department of Clinical and Experimental Medicine/Technical Audiology, Faculty of Health Sciences, Linko g € €tland, Sweden Department of ENT-Head Neck Surgery, Region Osterg o b c
a r t i c l e i n f o
a b s t r a c t
Article history: Received 7 September 2016 Received in revised form 12 March 2017 Accepted 23 September 2017 Available online xxx
Wolfram syndrome (WS) is caused by recessive mutations in the Wolfram syndrome 1 (WFS1) gene. Sensorineural hearing impairment (HI) is a frequent feature in WS and, furthermore, certain mutations in WFS1 cause nonsyndromic dominantly inherited low-frequency sensorineural HI. These two phenotypes are clinically distinct indicating that WFS1 is a reasonable candidate for genetic studies in patients with other phenotypes of HI. Here we have investigated, whether the variation in WFS1 has a pathogenic role in age-related hearing impairment (ARHI). WFS1 gene was investigated in a population sample of 518 Finnish adults born in 1938e1949 and representing variable hearing phenotypes. Identified variants were evaluated with respect to pathogenic potential. A rare mutation predicted to be pathogenic was found in a family with many members with impaired hearing. Twenty members were recruited to a segregation study and a detailed clinical examination. Heterozygous p.Tyr528His variant segregated completely with late-onset HI in which hearing deteriorated first at high frequencies and progressed to mid and low frequencies later in life. We report the first mutation in the WFS1 gene causing late-onset HI with audiogram configurations typical for ARHI. Monogenic forms of ARHI are rare and our results add WFS1 to the short list of such genes. © 2017 Elsevier B.V. All rights reserved.
Keywords: Age-related hearing impairment Presbyacusis Wolfram syndrome High-frequency hearing impairment
1. Introduction Wolfram syndrome (WS [MIM: 222300]) is a rare autosomal recessive disorder that is caused by mutations in the Wolfram Syndrome 1 (WFS1) gene (Wolfram and Wagener, 1938; Inoue et al., 1998). Patients with WS commonly have bilateral sensorineural hearing impairment (HI) affecting high frequencies, and their heterozygous family members have an increased risk of HI as well (Barrett et al., 1995; Ohata et al., 1998). Certain mutations in WFS1
Abbreviations: ARHI, age-related hearing impairment; BEHL, better ear hearing level; HI, hearing impairment; WFS1, Wolfram Syndrome 1; WS, Wolfram syndrome; LFSNHI, low-frequency sensorineural hearing impairment * Corresponding author. Research Unit of Clinical Neuroscience, University of Oulu, P.O. Box 5000, FI-90014 Oulu, Finland. € vuori). E-mail address: laura.kytovuori@oulu.fi (L. Kyto
also cause non-syndromic autosomal dominant low-frequency sensorineural hearing impairment (LFSNHI [MIM: 600965]) (Bespalova et al., 2001; Young et al., 2001). Age-related HI (ARHI) is a common type of adult-onset HI. The prevalence of ARHI has been reported to be 36.8% among men aged 54e66 years and 18.4% among women in Finland (Hannula et al., 2010). ARHI typically manifests with an audiogram configuration showing sloping at higher frequencies (Hannula et al., 2011). The genetic etiology of the trait is complex. A recent large-scale genome-wide association study has failed to replicate any of the previous associations indicating a polygenic nature of ARHI (Fransen et al., 2014). ARHI has been successfully modeled in mice, but corresponding genes in humans rarely cause late-onset HI (Johnson et al., 1997; Bork et al., 2001; Yan et al., 2013). Only few monogenic forms of HI resembling ARHI have been reported in the literature (Walsh et al., 2010; Oonk et al., 2013). The aim of the
https://doi.org/10.1016/j.heares.2017.09.013 0378-5955/© 2017 Elsevier B.V. All rights reserved.
€vuori, L., et al., A nonsynonymous mutation in the WFS1 gene in a Finnish family with age-related hearing Please cite this article in press as: Kyto impairment, Hearing Research (2017), https://doi.org/10.1016/j.heares.2017.09.013
€vuori et al. / Hearing Research xxx (2017) 1e5 L. Kyto
2
present study was to investigate, if the rare variants in WFS1 could be involved in the development of ARHI in Finnish subjects. 2. Subjects and methods The subjects (N ¼ 518) were randomly sampled from the population register in 2003 and it was required that the subjects were born in 1938e1949 and that they resided in the city of Oulu or in the surrounding areas (Hannula et al., 2010). Otological examination was performed by an ENT specialist at an office visit and their otological and audiological history was reviewed in a structured interview that was based on a previsit questionnaire. Pure tone audiometry was conducted according to ISO 8253-1 (1989) standard. HI was defined as better ear hearing level over the frequencies 0.5, 1, 2 and 4 kHz (BEHL0.5, 1, 2, 4 kHz) 20 dB HL (Stephens, 1996). The asymmetric or conductive HI was defined as previously (Hannula et al., 2010). For further analyses the subjects were divided in subgroups according to high-frequency HI (BEHL4, 6, 8 kHz 30 dB HL) and low-frequency HI (BEHL0.125, 0.25, 0.5 kHz 15 dB HL). The controls consisted of subjects who had BEHL0.5, 1, 2, 4 kHz < 20 dB, BEHL4, 6, 8 kHz < 20 dB, and BEHL0.125, 0.25, 0.5 kHz < 15 dB HL. History of noise exposure was screened with questions on exposure to occupational noise, leisure time noise and gunfire noise. The study protocol was approved by National Committee on Medical Research Ethics. All subjects gave their written informed consent. Amplification of WFS1 exon 8 was performed in three overlapping fragments using Phire Hot Start II DNA polymerase (Thermo Fisher Scientific, Waltham, MA, U.S.A.) in 280 subjects with HI fulfilling the aforementioned definitions. Sequencing was carried out using BigDyeTerminator v1.1 cycle sequencing kit (Applied Biosystems™, Thermo Fisher Scientific) and 3500xL Genetic Analyzer at Biocenter Oulu sequencing core facility. The discovered variants were evaluated using a consensus classifier PredictSNP (Bendl et al., 2014). Family history was examined for further selection of the patients. The carrier of the one putatively pathogenic variant reported high prevalence of HI among her family members. Therefore, all family members older than 40 years were invited to a segregation analysis and clinical examination that were performed in 2015 and that included the proband, her child and her eight siblings and 11 children of the siblings. 3. Results Hearing impairment (BEHL0.5, 1, 2, 4 kHz 20 dB HL) was diagnosed in 112 subjects. Moreover, high frequencies were affected (BEHL4, 6, 8 kHz 30 dB HL) in 255 subjects, and a pure highfrequency HI was found in 149 subjects. Among the subjects we discovered seven variants that were then evaluated as a possible cause of HI. Five of these variants were predicted to be deleterious (Table 1). The audiogram configurations of the five carriers were sloping at the high frequencies. The c.1582T > C transition (p.Tyr528His) was found in a woman (II-6), who reported several members with HI in her family (Fig. 1). The p.Tyr528His mutation was predicted to be pathogenic in silico, and it has been found once in 120,122 alleles in ExAC database (rs761976067; http://exac. broadinstitute.org, accessed in January 2017). The proband had mild ARHI (BEHL0.5, 1, 2, 4 kHz 38 dB HL) at the age of 65 years. The second clinical examination at the age of 76 years revealed progression of the HI (BEHL0.5, 1, 2, 4 kHz 48 dB HL). Review of the patient's charts showed that she had had a mild HI at high frequencies (BEHL4, 6, 8 kHz 28 dB HL) in her first audiogram at the age of 45 years (Fig. 2). Otological and audiological risk factors for HI were enquired from all family members. The most common risk factor for HI was
noise exposure. All men and two women reported some exposure to noise. None of the subjects had a history of ototoxic medication, or central nervous system infection. In addition, none of the subjects had optic atrophy. Clinical otological examination did not reveal abnormalities. Four subjects reported onset of HI between 15 and 40 years of age and 16 subjects at 40 years of age and all of them reported slow progression of HI. One mutation carrier had an asymmetric HI but, as magnetic resonance imaging did not reveal retrocochlear pathology, his better ear was included in the analyses. A daughter of II-7 was excluded from the analyses on the basis of a mixed HI in the right ear and high-frequency sensorineural HI on the left. She did not carry p.Tyr528His or any other putatively pathogenic mutations in the WFS1 gene. The audiogram configuration on the left was atypical, as it partly resembled a U-shaped one combined with a deep dip in the two highest frequencies. Such a finding is not typical for ARHI. The remaining subjects had symmetric sensorineural HI in audiograms. BEHL was worse in subjects with p.Tyr528His than in those with the homozygous wild-type variant (Fig. 1B). The mean difference was 8e15 dB at frequencies 0.125, 0.250, 0.5 and 1 kHz among subjects in generation II, while the mean hearing levels were similar at frequencies 2, 4, 6 and 8 kHz. In generation III the subjects with wild-type genotype had a minor drop in the audiogram within the highest frequencies. However, III-4 harboring the mutation had an explicit steeply sloping audiogram configuration and sensorineural HI in both ears. His BEHL0.5, 1, 2, 4 kHz was 35 dB at the age of 57 years. Moreover, his first hearing tests had already revealed high-frequency HI (BEHL4, 6, 8 kHz 48 dB) at the age of 45 years, which had progressed to the present level of 77 dB HL. For the comparison, his male cousin (III-9) with the worst hearing had HL of 13 dB and 43 dB at the age of 53 years with respect to the mid and high frequencies. 4. Discussion We found that p.Tyr528His was pathogenic in silico and that it segregated with late-onset HI clinically resembling ARHI. Interestingly, homozygous p.Tyr528Asp mutation has been found in two unrelated patients with WS and HI (Zalloua et al., 2008; Aloi et al., 2012). Furthermore, a homozygous nonsense mutation p.Tyr528* has been detected in a boy with WS and HI (Colosimo et al., 2003) suggesting that the nucleotides in the codon of amino acid residue 528 are vulnerable for mutations. A systematic review has shown that 48% of WS patients manifest HI with a median onset-age of 14 years (de Heredia et al., 2013). WFS1-accociated dominantly inherited LFSNHI is a clinical entity characterized by an ascending audiogram configuration. The age of onset of LFSNHI varies, but usually HI has been noted by the end of the second decade (Young et al., 2001; Lesperance et al., 2003; Fukuoka et al., 2007). HI is progressive, but a rather stereotypic audiogram configuration is recognizable even in the eldest family members (Lesperance et al., 2003; Pennings et al., 2003). The mutation carriers in our family had high-frequency sloping audiograms consistent with the most prevalent audiogram configuration in ARHI (Hannula et al., 2011). Moreover, the audiogram configurations did not resemble WFS1-related LFSNHI at any age (Fig. 2). Almost all Finnish men have at least some exposure to gunfire noise owing to mandatory military service and hunting as a popular leisure time activity. Indeed, all the men in the family reported a history of some noise exposure. Unfortunately, there was only one mutation carrier among the three descendants of the mutation carriers. Studies among the fourth generation and findings in an independent family will be required to confirm the association of
€ vuori, L., et al., A nonsynonymous mutation in the WFS1 gene in a Finnish family with age-related hearing Please cite this article in press as: Kyto impairment, Hearing Research (2017), https://doi.org/10.1016/j.heares.2017.09.013
€vuori et al. / Hearing Research xxx (2017) 1e5 L. Kyto
3
Table 1 Five rare variants in WFS1 that were evaluated as a possible cause of HI in Finnish subjects with variable hearing phenotypes. Alleles in ExACa Nucleotide change
Amino acid change
All populations
Finland
Controlsb (N ¼ 149)
PredictSNPc (Confidence)
Type of HId
Previous findings
c.1209G > T
p.Glu403Asp
8
5
0
Deleterious (61%)
High
c.1582T > C
p.Tyr528His
1
0
0
Deleterious (72%)
Mid and High
Found in patients with HI and €vuori et al., 2013) DM (Kyto p.Tyr528Asp and p.Tyr528* are pathogenic WS mutations (Colosimo et al., 2003; Zalloua et al., 2008; Aloi et al., 2012)
c.1976T > G c.2026C > T c.2084G > A
p.Val659Gly p.Arg676Cys p.Gly695Asp
0 10 6
0 0 2
0 0 1
Deleterious (51%) Deleterious (61%) Deleterious (87%)
High High Mid and High
a b c d
p.Gly695Val is pathogenic WS mutation (Inoue et al., 1998)
ExAC database, http://exac.broadinstitute.org, total N (all populations) > 120,000, total N (Finland) > 6500. Subjects who had BEHL0.5, 1,2, 4 kHz < 20 dB, BEHL4, 6, 8 kHz < 20 dB, and BEHL0.125, 0.25, 0.5 kHz < 15 dB HL. Bendl et al., 2014. High, BEHL 4, 6, 8 kHz 30 dB, Mid, BEHL 0.5, 1, 2, 4 kHz 20 dB.
the WFS1 in ARHI. Interestingly, it has been suggested that an impairment in the unfolded protein response (UPR) is involved in the pathomechanism of ARHI (Wang et al., 2015) and that the wolframin protein participates in the signaling pathway of UPR
(Fonseca et al., 2005). When the incidence of a trait is age-related, the contribution of rare variants may be difficult to estimate while the phenotype can be still undeveloped. A recent study supports polygenic nature of
Fig. 1. Segregation of the heterozygous p.Tyr528His variant in a Finnish family. (A) Pedigree of the family. Arrow, proband; open circle, asymptomatic female; open square, asymptomatic male; dark gray circle, female with hearing impairment (HI) and with p.Tyr528His; dark gray square, male with HI and with p.Tyr528His; light gray circle, female with HI; light gray square, male with HI; ,-, carrier of p.Tyr528His; ,,, wild type. Ages are shown under the genotype symbol. (B) Audiograms of the family members in different generations. Carriers of p.Tyr528His and subjects with wild type genotype are presented separately in each generation.
€vuori, L., et al., A nonsynonymous mutation in the WFS1 gene in a Finnish family with age-related hearing Please cite this article in press as: Kyto impairment, Hearing Research (2017), https://doi.org/10.1016/j.heares.2017.09.013
€vuori et al. / Hearing Research xxx (2017) 1e5 L. Kyto
4
Fig. 2. Progression of HI in the family with p.Tyr528His in the WFS1 gene. Audiograms represent better ear hearing thresholds of five subjects harboring the p.Tyr528His variant and two subjects with the wild type (WT) genotype. The ages are shown on the right side of each panel.
ARHI and suggests that there are no major causative genes (Fransen et al., 2014). For future investigations, we strongly recommend the use of families with high prevalence of late-onset HI. ARHI has not been investigated with the same intensity as HI in children, even though the prevalence of ARHI outnumbers several-fold that of HI in children. Improved genetic diagnostics could bring the younger generation into clinical examinations earlier. To conclude, our findings show that mutations in WFS1 play a role in age-related HI in addition to WS-related HI and dominantly inherited HI affecting low frequencies. Conflict of interest, and author contributions €vuori designed The authors declare no conflict of interest. L. Kyto the study, did the molecular investigations, and wrote the first draft. S. Hannula collected the samples and did the clinical exam€ki-Torkko, and M. Sorri supervised the clinical study. inations. E. Ma K. Majamaa designed the study and supervised the project. All authors revised the manuscript. All authors have approved the final manuscript. Acknowledgements The authors acknowledge the technical assistance of Ms. Anja Heikkinen. The study was supported by grants from the Sigrid Juselius Foundation, Medical Research Center, University of Oulu and Oulu University Hospital, and State research funding from Oulu University Hospital. The sponsors have not been involved in designing or conduction of this study. References Aloi, C., Salina, A., Pasquali, L., Lugani, F., Perri, K., Russo, C., Tallone, R., Ghiggeri, G.M., Lorini, R., d'Annunzio, G., 2012. Wolfram syndrome: new
mutations, different phenotype. PLoS One 7, e29150. Barrett, T.G., Bundey, S.E., Macleod, A.F., 1995. Neurodegeneration and diabetes: UK nationwide study of wolfram (DIDMOAD) syndrome. Lancet 346, 1458e1463. Bendl, J., Stourac, J., Salanda, O., Pavelka, A., Wieben, E.D., Zendulka, J., Brezovsky, J., Damborsky, J., 2014. PredictSNP: robust and accurate consensus classifier for prediction of disease-related mutations. PLoS Comput. Biol. 10 e1003440. Bespalova, I.N., Van Camp, G., Bom, S.J., Brown, D.J., Cryns, K., DeWan, A.T., Erson, A.E., Flothmann, K., Kunst, H.P., Kurnool, P., Sivakumaran, T.A., Cremers, C.W., Leal, S.M., Burmeister, M., Lesperance, M.M., 2001. Mutations in the wolfram syndrome 1 gene (WFS1) are a common cause of low frequency sensorineural hearing loss. Hum. Mol. Genet. 10, 2501e2508. Bork, J.M., Peters, L.M., Riazuddin, S., Bernstein, S.L., Ahmed, Z.M., Ness, S.L., Polomeno, R., Ramesh, A., Schloss, M., Srisailpathy, C.R., Wayne, S., Bellman, S., Desmukh, D., Ahmed, Z., Khan, S.N., Kaloustian, V.M., Li, X.C., Lalwani, A., Riazuddin, S., Bitner-Glindzicz, M., Nance, W.E., Liu, X.Z., Wistow, G., Smith, R.J., Griffith, A.J., Wilcox, E.R., Friedman, T.B., Morell, R.J., 2001. Usher syndrome 1D and nonsyndromic autosomal recessive deafness DFNB12 are caused by allelic mutations of the novel cadherin-like gene CDH23. Am. J. Hum. Genet. 68, 26e37. Colosimo, A., Guida, V., Rigoli, L., Di Bella, C., De Luca, A., Briuglia, S., Stuppia, L., Salpietro, D.C., Dallapiccola, B., 2003. Molecular detection of novel WFS1 mutations in patients with wolfram syndrome by a DHPLC-based assay. Hum. Mutat. 21, 622e629. ries, R., Nunes, V., 2013. Genotypic classification of patients de Heredia, M.L., Cle with Wolfram syndrome: insights into the natural history of the disease and correlation with phenotype. Genet. Med. 15, 497e506. Fonseca, S.G., Fukuma, M., Lipson, K.L., Nguyen, L.X., Allen, J.R., Oka, Y., Urano, F., 2005. WFS1 is a novel component of the unfolded protein response and maintains homeostasis of the endoplasmic reticulum in pancreatic beta-cells. J. Biol. Chem. 280, 39609e39615. Fransen, E., Bonneux, S., Corneveaux, J.J., Schrauwen, I., Di Berardino, F., White, C.H., Ohmen, J.D., Van de Heyning, P., Ambrosetti, U., Huentelman, M.J., Van Camp, G., Friedman, R.A., 2014. Genome-wide association analysis demonstrates the highly polygenic character of age-related hearing impairment. Eur. J. Hum. Genet. 23, 110e115. Fukuoka, H., Kanda, Y., Ohta, S., Usami, S.I., 2007. Mutations in the WFS1 gene are a frequent cause of autosomal dominant nonsyndromic low-frequency hearing loss in Japanese. J. Hum. Genet. 52, 510e515. Hannula, S., M€ aki-Torkko, E., Majamaa, K., Sorri, M., 2010. Hearing in a 54- to 66year-old population in northern Finland. Int. J. Audiol. 49, 920e927. €ki-Torkko, E., 2011. Audiogram Hannula, S., Bloigu, R., Majamaa, K., Sorri, M., Ma configurations among older adults: prevalence and relation to self-reported hearing problems. Int. J. Audiol. 50, 793e801. Inoue, H., Tanizawa, Y., Wasson, J., Behn, P., Kalidas, K., Bernal-Mizrachi, E.,
€ vuori, L., et al., A nonsynonymous mutation in the WFS1 gene in a Finnish family with age-related hearing Please cite this article in press as: Kyto impairment, Hearing Research (2017), https://doi.org/10.1016/j.heares.2017.09.013
€vuori et al. / Hearing Research xxx (2017) 1e5 L. Kyto Mueckler, M., Marshall, H., Donis-Keller, H., Crock, P., Rogers, D., Mikuni, M., Kumashiro, H., Higashi, K., Sobue, G., Oka, Y., Permutt, M.A., 1998. A gene encoding a transmembrane protein is mutated in patients with diabetes mellitus and optic atrophy (wolfram syndrome). Nat. Genet. 20, 143e148. Johnson, K.R., Erway, L.C., Cook, S.A., Willott, J.F., Zheng, Q.Y., 1997. A major gene affecting age-related hearing loss in C57BL/6J mice. Hear. Res. 114, 83e92. €vuori, L., Seppa €nen, A., Martikainen, M.H., Moilanen, J.S., Kamppari, S., Kyto €nen, P., Ro € nnemaa, T., Majamaa, K., 2013. WFS1 S€ arkioja, T., Remes, A.M., R€ asa variants in Finnish patients with diabetes mellitus, sensorineural hearing impairment or optic atrophy, and in suicide victims. J. Hum. Genet. 58, 495e500. Lesperance, M.M., Hall, J.W., San Agustin, T.B., Leal, S.M., 2003. Mutations in the Wolfram syndrome type 1 gene (WFS1) define a clinical entity of dominant lowfrequency sensorineural hearing loss. Arch. Otolaryngol. Head Neck Surg. 129, 411e420. Ohata, T., Koizumi, A., Kayo, T., Shoji, Y., Watanabe, A., Monoh, K., Higashi, K., Ito, S., Ogawa, O., Wada, Y., Takada, G., 1998. Evidence of an increased risk of hearing loss in heterozygous carriers in a wolfram syndrome family. Hum. Genet. 103, 470e474. Oonk, A.M., Leijendeckers, J.M., Lammers, E.M., Weegerink, N.J., Oostrik, J., Beynon, A.J., Huygen, P.L., Kunst, H.P., Kremer, H., Snik, A.F., Pennings, R.J., 2013. Progressive hereditary hearing impairment caused by a MYO6 mutation resembles presbyacusis. Hear. Res. 299, 88e98. Pennings, R.J., Bom, S.J., Cryns, K., Flothmann, K., Huygen, P.L., Kremer, H., Van Camp, G., Cremers, C.W., 2003. Progression of low-frequency sensorineural hearing loss (DFNA6/14-WFS1). Arch. Otolaryngol. Head Neck Surg. 129, 421e426. Stephens, D., 1996. Study Group on Terminology, Definitions and Hearing Assessment. European Work Group on Genetics of Hearing Impairment. European Commission Directorate, Biomedical and Health Research Program (HEAR) Info letter, 2.
5
Walsh, T., Pierce, S.B., Lenz, D.R., Brownstein, Z., Dagan-Rosenfeld, O., Shahin, H., Roeb, W., McCarthy, S., Nord, A.S., Gordon, C.R., Ben-Neriah, Z., Sebat, J., Kanaan, M., Lee, M.K., Frydman, M., King, M.C., Avraham, K.B., 2010. Genomic duplication and overexpression of TJP2/ZO-2 leads to altered expression of apoptosis genes in progressive nonsyndromic hearing loss DFNA51. Am. J. Hum. Genet. 87, 101e109. Wang, W., Sun, Y., Chen, S., Zhou, X., Wu, X., Kong, W., Kong, W., 2015. Impaired unfolded protein response in the degeneration of cochlea cells in a mouse model of age-related hearing loss. Exp. Gerontol. 70, 61e70. Wolfram, D.J., Wagener, H.P., 1938. Diabetes mellitus and simple optic atrophy among siblings: report of four cases. Mayo Clin. Proc. 13, 715e718. Yan, D., Zhu, Y., Walsh, T., Xie, D., Yuan, H., Sirmaci, A., Fujikawa, T., Wong, A.C., Loh, T.L., Du, L., Grati, M., Vlajkovic, S.M., Blanton, S., Ryan, A.F., Chen, Z.Y., Thorne, P.R., Kachar, B., Tekin, M., Zhao, H.B., Housley, G.D., King, M.C., Liu, X.Z., 2013. Mutation of the ATP-gated P2X(2) receptor leads to progressive hearing loss and increased susceptibility to noise. Proc. Natl. Acad. Sci. U. S. A. 110, 2228e2233. Young, T.L., Ives, E., Lynch, E., Person, R., Snook, S., MacLaren, L., Cater, T., Griffin, A., Fernandez, B., Lee, M.K., King, M.C., 2001. Non-syndromic progressive hearing loss DFNA38 is caused by heterozygous missense mutation in the wolfram syndrome gene WFS1. Hum. Mol. Genet. 10, 2509e2514. Zalloua, P.A., Azar, S.T., Delepine, M., Makhoul, N.J., Blanc, H., Sanyoura, M., Lavergne, A., Stankov, K., Lemainque, A., Baz, P., Julier, C., 2008. WFS1 mutations are frequent monogenic causes of juvenile-onset diabetes mellitus in Lebanon. Hum. Mol. Genet. 17, 4012e4021.
Web resources ExAC database, http://exac.broadinstitute.org. Nature, https://doi.org/10.1038/ nature19057.
€vuori, L., et al., A nonsynonymous mutation in the WFS1 gene in a Finnish family with age-related hearing Please cite this article in press as: Kyto impairment, Hearing Research (2017), https://doi.org/10.1016/j.heares.2017.09.013