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Vallian Broojeni J, Kazemi A, Rezaei H, Vallian S. Exome sequencing identifies novel variants associated with non-syndromic hearing loss in the Iranian population. PLoS One 2023; 18:e0289247. [PMID: 37561809 PMCID: PMC10414579 DOI: 10.1371/journal.pone.0289247] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 07/13/2023] [Indexed: 08/12/2023] Open
Abstract
Autosomal recessive non-syndromic hearing loss (ARNSHL) is a public health concern in the Iranian population, with an incidence of 1 in 166 live births. In the present study, the whole exome sequencing (WES) method was applied to identify the mutation spectrum of NSHL patients negative for GJB2 gene mutations. First, using ARMS PCR followed by Sanger sequencing of the GJB2 gene, 63.15% of mutations in patients with NSHL were identified. Among the identified mutations in GJB2:p.Val43Met and p.Gly21Arg were novel. The remaining patients were subjected to WES, which identified novel mutations including MYO15A:p.Gly39LeufsTer188, ADGRV1:p.Ser5918ValfsTer23, MYO7A: c.5856+2T>c (splicing mutation), FGF3:p.Ser156Cys. The present study emphasized the application of WES as an effective method for molecular diagnosis of NSHL patients negative for GJB2 gene mutations in the Iranian population.
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Affiliation(s)
- Jalal Vallian Broojeni
- Department of Cell and Molecular Biology& Microbiology, Faculty of Science and Technology, University of Isfahan, Isfahan, IR, Iran
| | - Arezu Kazemi
- Department of Cell and Molecular Biology& Microbiology, Faculty of Science and Technology, University of Isfahan, Isfahan, IR, Iran
| | - Halimeh Rezaei
- Department of Cell and Molecular Biology& Microbiology, Faculty of Science and Technology, University of Isfahan, Isfahan, IR, Iran
| | - Sadeq Vallian
- Department of Cell and Molecular Biology& Microbiology, Faculty of Science and Technology, University of Isfahan, Isfahan, IR, Iran
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2
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Abbaspour Rodbaneh E, Panahi M, Rahimi B, Mokabber H, Farajollahi R, Davarnia B. GJB2 mutations in Iranian Azeri population with autosomal recessive nonsyndromic hearing loss (ARNSHL): First report of c.238 C>A mutation in Iran. J Clin Lab Anal 2021; 35:e24024. [PMID: 34581455 PMCID: PMC8605150 DOI: 10.1002/jcla.24024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 09/09/2021] [Accepted: 09/14/2021] [Indexed: 12/18/2022] Open
Abstract
Objective Autosomal‐recessive nonsyndromic hearing loss (ARNSHL) is a heterogeneous genetic disorder. Mutations in the gap junction protein beta 2 (GJB2) gene, encoding connexin 26, are a significant cause of ARNSHL in different ethnic groups. This study aimed to identify the frequency and type of GJB2 mutations in the Iranian Azeri population. Methods Fifty unrelated families presenting ARNSHL in Ardabil Province, the northwest of Iran, were studied to determine the frequency and type of GJB2 mutations leading to ARNSHL. ARMS‐PCR screened all DNA samples to detect c.35delG; p. Gly12Val mutation. In addition, normal samples for c.35delG; p. Gly12Val were analyzed by direct sequencing for other GJB2 mutations. Result Of the fifty families, 13 (26%) showed a GJB2 gene mutation, with c.35delG; p. Gly12Val mutation was the most prevalent one that occurred in eight (61.5%) out of the 13 families. Of the families, two were homozygous for c.358‐360delGAC; p. Glu120del mutation, and one was homozygous for c.290dupA; p. Tyr97Ter and c.299–300delAT; p. His100Arg mutations. Also, we detected a novel mutation, c.238C>A; p. Gln80lys, in one of the families. Conclusion Our findings are comparable to previous studies, indicating c.35d3lG; p. Gly12Val mutation in the GJB2 gene is the most common cause of GJB2‐related hearing loss in the Iranian Azeri population. Furthermore, our study highlights the significance of ARNSHL screening programs of live births based on local population data in Iran.
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Affiliation(s)
| | - Mohammad Panahi
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Bahareh Rahimi
- Department of Medical Biotechnology, Faculty of Allied Medical Sciences, Iran University of Medical Sciences, Tehran, Iran
| | - Haleh Mokabber
- Medical Genetics and Pathology, Ardabil University of Medical Sciences, Ardabil, Iran
| | - Reza Farajollahi
- Medical Genetics and Pathology, Ardabil University of Medical Sciences, Ardabil, Iran.,Ardabil Welfare Organization, Ardabil, Iran
| | - Behzad Davarnia
- Medical Genetics and Pathology, Ardabil University of Medical Sciences, Ardabil, Iran
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3
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Dianatpour M, Smith E, Hashemi SB, Farazifard MA, Nezafat N, Razban V, Mani A. Identification of homozygous mutations for hearing loss. Gene 2021; 778:145464. [PMID: 33524517 DOI: 10.1016/j.gene.2021.145464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Hearing loss is the most common sensory disorder worldwide, affecting about 1 out of every 1000 newborns. The disease has major genetic components, and can be inherited as a single gene disorder either in autosomal dominant or recessive fashions. Due to the high rate of consanguineous unions, Iran has one of the highest prevalence of autosomal recessive nonsyndromic deafness (ARNSD) in the world. METHODS We carried out a genetic screening of ten Iranian kindreds with more than one offspring affected by ARNSD caused by consanguineous unions. Sanger sequencing and whole exome sequencing together with in silico 3D structure modeling and protein stability prediction were used to identify the underlying disease causing genes. CONCLUSION We identified the causes of deafness in all 10 kindred. In six kindreds homozygous mutations were identified in GJB2 gene by Sanger sequencing. By using whole exome sequencing (WES), a homozygous missense mutation was identified in ESRRB gene as the first ever reported disease gene in Iran. Also two novel homozygous frameshift and missense mutations were identified in MYO15A gene and one previously reported mutation in TMC1 gene in three independent kindred. Our study shows the efficacy of WES for unraveling new pathogenic mutations in ARNSD patients and expands the spectrum of genes contributing to ARNSD in the Iranian population. The findings of our study can facilitate future genetic screening of patients with ARNSD , early screening and optimal design of novel therapeutics.
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Affiliation(s)
- Mehdi Dianatpour
- Department of Medical Genetic, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran; Stem Cells Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Emily Smith
- Department of Internal Medicine, Yale Cardiovascular Research Center, Yale University, School of Medicine, New Haven, CT, United States.
| | - Seyed Basir Hashemi
- Department of Otolaryngology, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad A Farazifard
- Department of Medical Genetic, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Navid Nezafat
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Vahid Razban
- Stem Cells Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Molecular Medicine, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Arya Mani
- Department of Internal Medicine, Yale Cardiovascular Research Center, Yale University, School of Medicine, New Haven, CT, United States.
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4
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Falah M, Houshmand M, Balali M, Asghari A, Bagher Z, Alizadeh R, Farhadi M. Role of GJB2 and GJB6 in Iranian Nonsyndromic Hearing Impairment: From Molecular Analysis to Literature Reviews. Fetal Pediatr Pathol 2020; 39:1-12. [PMID: 31215297 DOI: 10.1080/15513815.2019.1627625] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background: Hearing impairment (HI) is a heterogeneous disorder. GJB2 and GJB6 genes are typically the first line of genetic screening before proceeding to any massive parallel sequencing. We evaluated the clinical utility of GJB2 and GJB6 testing in the Iranian population. Methods: GJB2 and GJB6 were sequenced. PubMed and Google Scholar were searched for Iranian publications on deletions in the DFNB1 locus. Results: We detected mutations of GJB2 in 16.5%, and no mutations of GJB6. Literature review revealed no reports of mutations of GJB6 in the Iranian population. Conclusion: This data and literature reviews indicate that GJB6 is not commonly responsible for Iranian nonsyndromic HI. Hence, the clinical utility of GJB6 genetic analysis as a first line for HI evaluation does not have the same utility as GJB2. The study is consistent with recent studies emphasizing the role of ethnicity in the selection of HI genetic testing strategy.
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Affiliation(s)
- Masoumeh Falah
- ENT and Head & Neck Research Center and Department, The Five Senses Institute, Hazrat Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Massoud Houshmand
- ENT and Head & Neck Research Center and Department, The Five Senses Institute, Hazrat Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran.,Department of Medical Genetics, National Institute for Genetic Engineering and Biotechnology, Tehran, Islamic Republic of Iran
| | - Maryam Balali
- ENT and Head & Neck Research Center and Department, The Five Senses Institute, Hazrat Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Alimohamad Asghari
- Skull Base Research Center, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Zohreh Bagher
- ENT and Head & Neck Research Center and Department, The Five Senses Institute, Hazrat Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Rafieh Alizadeh
- ENT and Head & Neck Research Center and Department, The Five Senses Institute, Hazrat Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Mohammad Farhadi
- ENT and Head & Neck Research Center and Department, The Five Senses Institute, Hazrat Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
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5
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Koohiyan M, Koohian F, Azadegan-Dehkordi F. GJB2-related hearing loss in central Iran: Review of the spectrum and frequency of gene mutations. Ann Hum Genet 2019; 84:107-113. [PMID: 31512227 DOI: 10.1111/ahg.12354] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 08/15/2019] [Accepted: 08/27/2019] [Indexed: 12/13/2022]
Abstract
Mutations in the GJB2 gene are a main cause of autosomal-recessive nonsyndromic hearing loss (ARNSHL) in many populations. Previous studies have estimated the average frequency of GJB2 mutations to be ∼16% in Iran, but would vary among different ethnic groups. Here, we have taken together and reviewed results from our two previous publications and data from searching other published mutation reports to provide a comprehensive collection of data for GJB2 mutations and HL in central Iran. In all, 332 unrelated families were included and analyzed for the prevalence and type of the GJB2 gene mutations. In total, the frequency of GJB2 mutations was found to be 16% in the central provinces, which is significantly higher than those identified in southern populations of Iran. Also, c.35delG was the most frequent mutation in the related population. The present study suggests that mutations in the GJB2 gene, especially c.35delG, are important causes of HL in central Iran and can be used as a basis of genetic counseling and clinical guidelines in this region.
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Affiliation(s)
- Mahbobeh Koohiyan
- Cancer Research Center, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Farideh Koohian
- Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
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6
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Koohiyan M, Azadegan-Dehkordi F, Koohian F, Abolhasani M, Hashemzadeh-Chaleshtori M. Genetics of hereditary hearing loss in east Iran population: A systematic review of GJB2 mutations. Intractable Rare Dis Res 2019; 8:172-178. [PMID: 31523594 PMCID: PMC6743427 DOI: 10.5582/irdr.2019.01070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mutations in the GJB2 gene are the most common cause of pre-lingual hearing loss (HL) worldwide. Previous studies have shown the frequency of GJB2 mutations to be 16% in Iran, but varies among different ethnic groups. Here, we have reviewed results from previous published mutation reports to provide a comprehensive collection of data for GJB2 mutations and HL in eastern Iran. We conducted a systematic literature review of PubMed, Google Scholar, Web of Science, and Science Direct databases for articles published before March, 2019. The literature search was performed by 2 independent researchers. The primary data of these studies including the number of samples, allelic frequency, and so on were extracted. Six studies involving 812 unrelated families from four different eastern provinces were included and analyzed for the type and prevalence of GJB2 mutations. A total of 19 different genetic variants were detected. GJB2 mutations were 8.8% in the studied eastern provinces, which was lower than that reported in northern populations of Iran. Moreover, a gradient in the frequency of GJB2 mutations from north to south Iran was observed. c.35delG was the most frequent mutation, accounting for 48.5% % of the populations studied. However, this mutation was absent in the Baluchi population. This review shows that particular rare mutations are frequent in some Iranian ethnic groups, and should be considered for genetic counselling.
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Affiliation(s)
- Mahbobeh Koohiyan
- Cancer Research Center, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Fatemeh Azadegan-Dehkordi
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Farideh Koohian
- Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Marziye Abolhasani
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Morteza Hashemzadeh-Chaleshtori
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
- Address correspondence to:Prof. Morteza Hashezadeh-Chaleshtori, Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Rahmatieh, Shahrekord 8813833435, Iran. E-mail:
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7
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Koohiyan M, Azadegan-Dehkordi F, Koohian F, Hashemzadeh-Chaleshtori M. Genetics of Hearing Loss in North Iran Population: An Update of Spectrum and Frequency of GJB2 Mutations. J Audiol Otol 2019; 23:175-180. [PMID: 31569309 PMCID: PMC6773957 DOI: 10.7874/jao.2019.00059] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Accepted: 06/27/2019] [Indexed: 11/22/2022] Open
Abstract
Diagnosis of pre-lingual hearing loss (HL) is difficult owing to the high number of genes responsible. The most frequent cause of HL is DFNB1 due to mutations in the GJB2 gene. It represents up to 40% of HL cases in some populations. In Iran, it has previously been shown that DFNB1 accounts for 16-18% of cases but varies among different ethnic groups. Here, we reviewed results from our three previous publications and data from other published mutation reports to provide a comprehensive collection of data for GJB2 mutations and HL in northern Iran. In total, 903 unrelated families from six different provinces, viz., Gilan, Mazandaran, Golestan, Ghazvin, Semnan, and Tehran, were included and analyzed for the type and prevalence of GJB2 mutations. A total of 23 different genetic variants were detected from which 18 GJB2 mutations were identified. GJB2 mutations were 20.7% in the studied northern provinces, which was significantly higher than that reported in southern populations of Iran. Moreover, a gradient in the frequency of GJB2 mutations from north to south Iran was observed. c.35delG was the most common mutation, accounting for 58.4% of the cases studied. This study suggests that c.35delG mutation in GJB2 is the most important cause of HL in northern Iran.
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Affiliation(s)
- Mahbobeh Koohiyan
- Cancer Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Fatemeh Azadegan-Dehkordi
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Farideh Koohian
- Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Morteza Hashemzadeh-Chaleshtori
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
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8
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Koohiyan M, Ahmadi A, Koohian F, Aghaei S, Amiri B, Hashemzadeh-Chaleshtori M. An update of spectrum and frequency of GJB2 mutations causing hearing loss in the south of Iran: A literature review. Int J Pediatr Otorhinolaryngol 2019; 119:136-140. [PMID: 30708180 DOI: 10.1016/j.ijporl.2019.01.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/21/2019] [Accepted: 01/23/2019] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Mutations in the GJB2 gene are a major cause of autosomal recessive non-syndromic HL (ARNSHL) in many populations. Previous studies have estimated the average frequency of GJB2 mutations to be between 16 and 18% in Iran, but would vary among different ethnic groups. Here, we have taken together and reviewed results from our three previous publications and data from search other published mutation reports to provide a comprehensive collection of data for GJB2 mutations and HL in the south of Iran. METHODS In all, 447 unrelated families were included and analyzed for the prevalence and type of the GJB2 gene mutations. RESULTS Totally, the frequency of GJB2 mutations was found to be 11.5% in the southern provinces studied which is significantly lower than that identified in Northern populations of Iran, and also a southwest to southeast Iranian gradient in the frequency of GJB2 mutations is suggested. CONCLUSIONS This study highlights the importance of establishing prevalence, based on the local population for screening and diagnostic programs of live births in Iran.
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Affiliation(s)
- Mahbobeh Koohiyan
- Cancer Research Center, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Amirhossein Ahmadi
- Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Farideh Koohian
- Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Shahrzad Aghaei
- Department of Molecular Medicine, School of Advanced Technologies, Shahrekord of Medical Sciences, Shahrekord, Iran
| | - Beheshteh Amiri
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Morteza Hashemzadeh-Chaleshtori
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran.
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9
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GJB2 mutations causing autosomal recessive non-syndromic hearing loss (ARNSHL) in two Iranian populations: Report of two novel variants. Int J Pediatr Otorhinolaryngol 2018; 107:121-126. [PMID: 29501291 DOI: 10.1016/j.ijporl.2018.01.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 01/14/2018] [Accepted: 01/15/2018] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Hereditary hearing loss (HL) is a noticeable concern in medicine all over the world. On average, 1 in 166 babies born are diagnosed with HL in Iran, which makes it a major public health issue. Autosomal recessive non-syndromic HL (ARNSHL) is the most prevalent form of HL. Although over 60 genes have been identified for ARNSHL, GJB2 mutations are the most prevalent causes of ARNSHL in many populations. Previous studies have estimated the average frequency of GJB2 mutations to be between 16 and 18% in Iran, but would vary among different ethnic groups. In the present study, we aimed to determine the frequency and mutation profile of 70 deaf patients from two different provinces (center and west) of Iran. METHODS We enrolled 70 Iranian deaf patients with ARNSHL from Isfahan (40 family) and Hamedan (30 family) provinces. After extraction of genomic DNA, the entire coding region of GJB2 was directly sequenced in all patients. Multiplex PCR was used for detection of del(GJB6-D13S1830) and del(GJB6-D13S1854) in the GJB6 gene. In silico analyses were also performed by available software tools. RESULTS A total of eleven different mutations were detected, nine of which were previously reported and the other two (c.130T > G and c.178T > G) were novel. Homozygous GJB2 mutations were observed in 22.5% and 20% of all the subjects from Isfahan and Hamedan provinces, respectively. c.35delG was the most frequent mutation. One compound heterozygous genotype (c.358_360delGAG/c.35delG) was observed for c.35delG. Screening for the two GJB6 deletions did not reveal any positive sample among heterozygous or GJB2 negative samples. CONCLUSIONS The present study suggests that mutations in the GJB2 gene specially c.35delG are important causes of ARNSHL in the center and west of Iran. Totally, 15% of the patients were heterozygous carriers. Further investigation is needed to detect the genetic cause of HL in the patients with monoallelic GJB2 mutations.
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Beheshtian M, Babanejad M, Azaiez H, Bazazzadegan N, Kolbe D, Sloan-Heggen C, Arzhangi S, Booth K, Mohseni M, Frees K, Azizi MH, Daneshi A, Farhadi M, Kahrizi K, Smith RJ, Najmabadi H. Heterogeneity of Hereditary Hearing Loss in Iran: a Comprehensive Review. ARCHIVES OF IRANIAN MEDICINE 2017; 19:720-728. [PMID: 27743438 DOI: 0161910/aim.0010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A significant contribution to the causes of hereditary hearing impairment comes from genetic factors. More than 120 genes and 160 loci have been identified to be involved in hearing impairment. Given that consanguine populations are more vulnerable to most inherited diseases, such as hereditary hearing loss (HHL), the genetic picture of HHL among the Iranian population, which consists of at least eight ethnic subgroups with a high rate of intermarriage, is expected to be highly heterogeneous. Using an electronic literature review through various databases such as PubMed, MEDLINE, and Scopus, we review the current picture of HHL in Iran. In this review, we present more than 39 deafness genes reported to cause non-syndromic HHL in Iran, of which the most prevalent causative genes include GJB2, SLC26A4, MYO15A, and MYO7A. In addition, we highlight some of the more common genetic causes of syndromic HHL in Iran. These results are of importance for further investigation and elucidation of the molecular basis of HHL in Iran and also for developing a national diagnostic tool tailored to the Iranian context enabling early and efficient diagnosis of hereditary hearing impairment.
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Affiliation(s)
- Maryam Beheshtian
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Mojgan Babanejad
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Hela Azaiez
- Department of Otolaryngology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Niloofar Bazazzadegan
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Diana Kolbe
- Department of Otolaryngology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Christina Sloan-Heggen
- Department of Otolaryngology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Sanaz Arzhangi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Kevin Booth
- Department of Otolaryngology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Marzieh Mohseni
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Kathy Frees
- Department of Otolaryngology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | | | - Ahmad Daneshi
- Head and Neck Surgery Department and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Farhadi
- Head and Neck Surgery Department and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Kimia Kahrizi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Richard Jh Smith
- Department of Otolaryngology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Hossein Najmabadi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
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Barashkov NA, Pshennikova VG, Posukh OL, Teryutin FM, Solovyev AV, Klarov LA, Romanov GP, Gotovtsev NN, Kozhevnikov AA, Kirillina EV, Sidorova OG, Vasilyevа LM, Fedotova EE, Morozov IV, Bondar AA, Solovyevа NA, Kononova SK, Rafailov AM, Sazonov NN, Alekseev AN, Tomsky MI, Dzhemileva LU, Khusnutdinova EK, Fedorova SA. Spectrum and Frequency of the GJB2 Gene Pathogenic Variants in a Large Cohort of Patients with Hearing Impairment Living in a Subarctic Region of Russia (the Sakha Republic). PLoS One 2016; 11:e0156300. [PMID: 27224056 PMCID: PMC4880331 DOI: 10.1371/journal.pone.0156300] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 05/12/2016] [Indexed: 11/29/2022] Open
Abstract
Pathogenic variants in the GJB2 gene, encoding connexin 26, are known to be a major cause of hearing impairment (HI). More than 300 allelic variants have been identified in the GJB2 gene. Spectrum and allelic frequencies of the GJB2 gene vary significantly among different ethnic groups worldwide. Until now, the spectrum and frequency of the pathogenic variants in exon 1, exon 2 and the flanking intronic regions of the GJB2 gene have not been described thoroughly in the Sakha Republic (Yakutia), which is located in a subarctic region in Russia. The complete sequencing of the non-coding and coding regions of the GJB2 gene was performed in 393 patients with HI (Yakuts—296, Russians—51, mixed and other ethnicities—46) and in 187 normal hearing individuals of Yakut (n = 107) and Russian (n = 80) populations. In the total sample (n = 580), we revealed 12 allelic variants of the GJB2 gene, 8 of which were recessive pathogenic variants. Ten genotypes with biallelic recessive pathogenic variants in the GJB2 gene (in a homozygous or a compound heterozygous state) were found in 192 out of 393 patients (48.85%). We found that the most frequent GJB2 pathogenic variant in the Yakut patients was c.-23+1G>A (51.82%) and that the second most frequent was c.109G>A (2.37%), followed by c.35delG (1.64%). Pathogenic variants с.35delG (22.34%), c.-23+1G>A (5.31%), and c.313_326del14 (2.12%) were found to be the most frequent among the Russian patients. The carrier frequencies of the c.-23+1G>A and с.109G>A pathogenic variants in the Yakut control group were 10.20% and 2.80%, respectively. The carrier frequencies of с.35delG and c.101T>C were identical (2.5%) in the Russian control group. We found that the contribution of the GJB2 gene pathogenic variants in HI in the population of the Sakha Republic (48.85%) was the highest among all of the previously studied regions of Asia. We suggest that extensive accumulation of the c.-23+1G>A pathogenic variant in the indigenous Yakut population (92.20% of all mutant chromosomes in patients) and an extremely high (10.20%) carrier frequency in the control group may indicate a possible selective advantage for the c.-23+1G>A carriers living in subarctic climate.
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Affiliation(s)
- Nikolay A. Barashkov
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
- * E-mail:
| | - Vera G. Pshennikova
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Olga L. Posukh
- Laboratory of Human Molecular Genetics, Federal Research Center, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation
- Novosibirsk State University, Novosibirsk, Russian Federation
| | - Fedor M. Teryutin
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Aisen V. Solovyev
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Leonid A. Klarov
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Department of Radiology, Republican Hospital # 2 –Center of Emergency Medicine, Ministry of Public Health of the Sakha Republic, Yakutsk, Russian Federation
| | - Georgii P. Romanov
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Nyurgun N. Gotovtsev
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Andrey A. Kozhevnikov
- Republican Centre of Professional Pathology, Republican Hospital # 2 –Center of Emergency Medicine, Ministry of Public Health of the Sakha Republic, Yakutsk, Russian Federation
| | - Elena V. Kirillina
- Institute of Foreign Philology and Regional Studies, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Oksana G. Sidorova
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
| | - Lena M. Vasilyevа
- Audiology-Logopaedic Centre, Republican Hospital #1– National Medical Centre, Ministry of Public Health of the Sakha Republic, Yakutsk, Russian Federation
| | - Elvira E. Fedotova
- Audiology-Logopaedic Centre, Republican Hospital #1– National Medical Centre, Ministry of Public Health of the Sakha Republic, Yakutsk, Russian Federation
| | - Igor V. Morozov
- Novosibirsk State University, Novosibirsk, Russian Federation
- SB RAS Genomics Core Facility, Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation
| | - Alexander A. Bondar
- SB RAS Genomics Core Facility, Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation
| | - Natalya A. Solovyevа
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Sardana K. Kononova
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Adyum M. Rafailov
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Nikolay N. Sazonov
- Department of Biochemistry and Biotechnology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
| | - Anatoliy N. Alekseev
- Institute of Humanitarian Research and Indigenous Peoples of the North, Siberian Branch of the Russian Academy of Sciences, Yakutsk, Russian Federation
| | - Mikhail I. Tomsky
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
| | - Lilya U. Dzhemileva
- Laboratory of Human Molecular Genetics, Institute of Biochemistry and Genetics, Ufa Scientific Centre, Russian Academy of Sciences, Ufa, Russian Federation
- Department of Immunology and Human Reproductive Health, Bashkir State Medical University, Ufa, Russian Federation
| | - Elza K. Khusnutdinova
- Laboratory of Human Molecular Genetics, Institute of Biochemistry and Genetics, Ufa Scientific Centre, Russian Academy of Sciences, Ufa, Russian Federation
- Department of Genetics and Fundamental Medicine, Bashkir State University, Ufa, Russian Federation
| | - Sardana A. Fedorova
- Department of Molecular Genetics, Federal State Budgetary Scientific Institution “Yakut Science Centre of Complex Medical Problems,” Yakutsk, Russian Federation
- Laboratory of Molecular Biology, Institute of Natural Sciences, M.K. Ammosov North-Eastern Federal University, Yakutsk, Russian Federation
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Chen WX, Huang Y, Yang XL, Duan B, Lu P, Wang Y, Xu ZM. The homozygote p.V27I/p.E114G variant of GJB2 is a putative indicator of nonsyndromic hearing loss in Chinese infants. Int J Pediatr Otorhinolaryngol 2016; 84:48-51. [PMID: 27063752 DOI: 10.1016/j.ijporl.2016.02.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 01/28/2016] [Accepted: 02/25/2016] [Indexed: 11/24/2022]
Abstract
The gap junction β2 (GJB2) gene is associated with more than half of the recessive forms of hereditary hearing loss (HHL). However, the correlation between p.V27I and p.E114G variants of GJB2 and hearing phenotype remains controversial. This study aimed to clarify possible roles of these variants in Chinese infants with nonsyndromic hearing loss (NSHL). Hearing and gene tests were conducted in 300 infants (aged 0-3 months) with NSHL and 484 normal infants (aged 0-3 months). The p.V27I and p.E114G variants appeared frequently in both NSHL patients and normal controls. The allele and haplotype frequencies of p.V27I and p.E114G in patients and controls were compared, but no significant difference was observed (p=0.44 and p=0.26, respectively). Moreover, genotype frequencies of the p.V27I variant showed no significant difference between the two groups (p=0.66). Interestingly, more homozygote p.V27I/p.E114G subjects were found in NSHL infants than in controls (5/484 and 13/300, respectively), most of whom (61.54%) had mild or moderate hearing losses. Our results indicate that homozygote p.V27I/p.E114G is associated with mild and moderate HHL.
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Affiliation(s)
- Wen-Xia Chen
- Department of Otolaryngology-Head and Neck Surgery, Children's hospital of Fudan University, Shanghai, China
| | - Yue Huang
- Department of Otolaryngology-Head and Neck Surgery, Children's hospital of Fudan University, Shanghai, China
| | - Xiao-Lin Yang
- Department of Otolaryngology-Head and Neck Surgery, Children's hospital of Fudan University, Shanghai, China
| | - Bo Duan
- Department of Otolaryngology-Head and Neck Surgery, Children's hospital of Fudan University, Shanghai, China
| | - Ping Lu
- Department of Otolaryngology-Head and Neck Surgery, Children's hospital of Fudan University, Shanghai, China
| | - Yan Wang
- Department of Otolaryngology-Head and Neck Surgery, Children's hospital of Fudan University, Shanghai, China
| | - Zheng-Min Xu
- Department of Otolaryngology-Head and Neck Surgery, Children's hospital of Fudan University, Shanghai, China.
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Mutation spectrum of autosomal recessive non-syndromic hearing loss in central Iran. Int J Pediatr Otorhinolaryngol 2015; 79:1892-5. [PMID: 26409293 DOI: 10.1016/j.ijporl.2015.08.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 08/25/2015] [Accepted: 08/27/2015] [Indexed: 01/05/2023]
Abstract
OBJECTIVE To identify the spectrum of mutations in connexin 26 gene and frequency of two deletions in connexin 30 gene in central Iran. METHODS After extraction of DNA from 300 blood samples, connexin 26 gene coding region was amplified using specific primers. PCR products were used for bidirectional sequencing. Multiplex PCR was used for detection of del(GJB6-D13S1830) and del(GJB6-D13S1854) in the GJB6 gene. RESULTS Eighteen different mutations including two novel variants in GJB2 gene were detected. The GJB2 mutations were observed in 23.3% of all the subjects. In addition, none of the deaf patients carried the del(GJB6-D13S1830) and del(GJB6-D13S1854) in the GJB6 gene. The 35delG mutation was the most common mutation, accounting for 32.65% of the mutant alleles. CONCLUSION The present study indicates that mutations in the GJB2 gene particularly 35delG are important causes for ARNSHL. 60% of the patients were heterozygous carriers. Thus, further investigation is needed to detect the genetic cause of hearing loss in patients with mono allelic mutations in the coding region of GJB2.
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14
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Amorini M, Romeo P, Bruno R, Galletti F, Di Bella C, Longo P, Briuglia S, Salpietro C, Rigoli L. Prevalence of Deafness-Associated Connexin-26 (GJB2) and Connexin-30 (GJB6) Pathogenic Alleles in a Large Patient Cohort from Eastern Sicily. Ann Hum Genet 2015; 79:341-349. [PMID: 26096904 DOI: 10.1111/ahg.12120] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 03/24/2015] [Indexed: 11/28/2022]
Abstract
Mutations in the gene encoding the gap junction protein connexin 26 (GJB2) and connexin 30 (GJB6) have been shown to be a major contributor to prelingual, sensorineural, nonsyndromic deafness. The aim of this study was to characterize and establish the prevalence of GJB2 and GJB6 gene alterations in 196 patients affected by sensorineural, nonsyndromic hearing loss, from Eastern Sicily. We performed sequence analysis of GJB2 and identified sequence variants in 68 out of 196 patients (34.7%); (28 homozygous for c.35delG, 22 compound heterozygous and 11 with only one variant allele). We found 12 different allelic variants, the most prevalent being c.35delG, which was found on 89 chromosomes (65.5%), followed by other alleles with different frequencies (p.E47X, c.-23+1G>A, p.L90P, p.R184W, p.M34T, c.167delT, p.R127H, p.M163V, p.V153I, p.W24X, and p.T8M). Importantly, for the first time we present the frequency and spectrum of GJB2 mutations in NSHL patients from Eastern Sicily. No alterations were found in the GJB6 gene, confirming that alterations in this gene are uncommon in our geographic area. Note that 65.3% and 23.5% of our patients, respectively were found to be negative or carriers by GJB2 molecular screening. This emphasizes the need to broaden the genetic analysis to other genes involved in hearing loss.
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Affiliation(s)
- Maria Amorini
- Department of Paediatrics, University of Messina, Italy
| | | | - Rocco Bruno
- Department of Experimental Medical-Surgery, Specialist and Odontostomatological Science, Otorhinolaringology and Auditory Microsurgery Unit, University of Messina, Italy
| | - Francesco Galletti
- Department of Experimental Medical-Surgery, Specialist and Odontostomatological Science, Otorhinolaringology and Auditory Microsurgery Unit, University of Messina, Italy
| | | | - Patrizia Longo
- Department of Experimental Medical-Surgery, Specialist and Odontostomatological Science, Otorhinolaringology and Auditory Microsurgery Unit, University of Messina, Italy
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15
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GJB2 c.−23+1G>A mutation is second most common mutation among Iranian individuals with autosomal recessive hearing loss. Eur Arch Otorhinolaryngol 2014; 272:2255-9. [DOI: 10.1007/s00405-014-3171-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 06/18/2014] [Indexed: 10/25/2022]
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16
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Chiang DY, Cuthbertson DW, Ruiz FR, Li N, Pereira FA. A coregulatory network of NR2F1 and microRNA-140. PLoS One 2013; 8:e83358. [PMID: 24349493 PMCID: PMC3857795 DOI: 10.1371/journal.pone.0083358] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 11/11/2013] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Both nuclear receptor subfamily 2 group F member 1 (NR2F1) and microRNAs (miRNAs) have been shown to play critical roles in the developing and functional inner ear. Based on previous studies suggesting interplay between NR2F1 and miRNAs, we investigated the coregulation between NR2F1 and miRNAs to better understand the regulatory mechanisms of inner ear development and functional maturation. RESULTS Using a bioinformatic approach, we identified 11 potential miRNAs that might coregulate target genes with NR2F1 and analyzed their targets and potential roles in physiology and disease. We selected 6 miRNAs to analyze using quantitative real-time (qRT) -PCR and found that miR-140 is significantly down-regulated by 4.5-fold (P=0.004) in the inner ear of NR2F1 knockout (Nr2f1(-/-)) mice compared to wild-type littermates but is unchanged in the brain. Based on this, we performed chromatin-immunoprecipitation followed by qRT-PCR and confirmed that NR2F1 directly binds and regulates both miR-140 and Klf9 in vivo. Furthermore, we performed luciferase reporter assay and showed that miR-140 mimic directly regulates KLF9-3'UTR, thereby establishing and validating an example coregulatory network involving NR2F1, miR-140, and Klf9. CONCLUSIONS We have described and experimentally validated a novel tissue-dependent coregulatory network for NR2F1, miR-140, and Klf9 in the inner ear and we propose the existence of many such coregulatory networks important for both inner ear development and function.
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Affiliation(s)
- David Y. Chiang
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, Texas, United States of America
| | - David W. Cuthbertson
- Bobby R. Alford Department of Otolaryngology- Head and Neck Surgery, Baylor College of Medicine, Houston, Texas, United States of America
| | - Fernanda R. Ruiz
- Huffington Center on Aging and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Na Li
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Fred A. Pereira
- Bobby R. Alford Department of Otolaryngology- Head and Neck Surgery, Baylor College of Medicine, Houston, Texas, United States of America
- Huffington Center on Aging and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
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Chan DK, Chang KW. GJB2-associated hearing loss: Systematic review of worldwide prevalence, genotype, and auditory phenotype. Laryngoscope 2013; 124:E34-53. [DOI: 10.1002/lary.24332] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2013] [Indexed: 12/17/2022]
Affiliation(s)
- Dylan K. Chan
- Department of Otolaryngology-Head and Neck Surgery; University of California; San Francisco U.S.A
| | - Kay W. Chang
- Department of Otolaryngology-Head and Neck Surgery; Stanford University School of Medicine; Stanford California U.S.A
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Manzoli GN, Abe-Sandes K, Bittles AH, da Silva DSD, Fernandes LDC, Paulon RMC, de Castro ICS, Padovani CMCA, Acosta AX. Non-syndromic hearing impairment in a multi-ethnic population of Northeastern Brazil. Int J Pediatr Otorhinolaryngol 2013; 77:1077-82. [PMID: 23684175 DOI: 10.1016/j.ijporl.2013.04.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Revised: 03/30/2013] [Accepted: 04/01/2013] [Indexed: 01/28/2023]
Abstract
OBJECTIVE There are many hearing impaired individuals in Monte Santo, a rural municipality in the state of Bahia, Brazil, including multiple familial cases strongly suggestive of a genetic aetiology. METHODS The present study investigated 81 subjects with hearing impairment (HI) recruited from 36 families. Mutations often associated with HI, i.e. the DFNB1 mutations c.35delG in GJB2, deletions del(GJB6-D13S1830) and del(GJB6-D13S1854), and A1555G in the mitochondrial gene MTRNR1 were initially analyzed, with additional mutations in GJB2 identified by sequencing the coding region of the gene. RESULTS Seven different mutations were present in GJB2 with mutations c.35delG and p.Arg75Gln, which are known to be pathogenic, identified in 37.0% of the subjects. Individuals homozygous for the c.35delG mutation were diagnosed in eight families, corresponding to 24.7% of unrelated individuals with nonsyndromic hearing impairment (NSHI), and an additional heterozygote for this mutation was present in a single family. Ten individuals (12.4%) in another family were heterozygous for the mutation p.Arg75Gln. CONCLUSIONS Significant heterogeneity was observed in the alleles and patterns of NSHI inheritance among the subjects studied, probably due to the extensive inter-ethnic admixture that characterizes the peoples of Brazil, together with a high prevalence of community endogamy and consanguineous marriage.
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Affiliation(s)
- Gabrielle N Manzoli
- Advanced Laboratory of Public Health/Gonçalo Moniz Research Center (CPqGM), Oswaldo Cruz Foundation (FIOCRUZ), Salvador, Bahia, Brazil
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Trabelsi M, Bahri W, Habibi M, Zainine R, Maazoul F, Ghazi B, Chaabouni H, Mrad R. GJB2 and GJB6 screening in Tunisian patients with autosomal recessive deafness. Int J Pediatr Otorhinolaryngol 2013; 77:714-6. [PMID: 23434199 DOI: 10.1016/j.ijporl.2013.01.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 01/18/2013] [Accepted: 01/26/2013] [Indexed: 10/27/2022]
Abstract
UNLABELLED Autosomal recessive nonsyndromic deafness (ARNSD or DFNB) is a very common genetically heterogenous disorder. Although DFNB1 mutations are known to be the most frequent cause of this disorder, they are largely dependent on ethnic groups. The aims of our study are to specify the prevalence and the spectrum of GJB2 mutations as well as the prevalence of GJB6 large deletion in Tunisian population. PATIENTS AND METHODS 95 unrelated patients with moderate to severe sensorineural hearing loss have been tested. The GJB2 coding region has been studied by PCR/Sequencing and the del(GJB6-D13S1830) mutation has been screened by fluorescent PCR multiplex. RESULTS 27.36% of patients present mutations on both alleles of GJB2 gene and no one has the del(GJB6-D13S1830) mutation. The c.35delG mutation represents 86.5% of GJB2 deafness alleles and is found in homozygous state in 22 patients and in heterozygous state in one patient. Four other mutations are detected in four probands: two are compound heterozygous for the p.V37I/p.E47X and the c.35delG/p.R184P mutations, and two are homozygous for the p.E47X and the c.333-334delAA mutations. CONCLUSION Our results showed that c.35delG is the most common but not the only GJB2 mutation and that the del(GJB6-del D13S1830) is absent in our cohort. Consequently, we propose a systematic sequencing of GJB2 coding region for ARNSD Tunisian patients and we suggest additional studies to specify the real prevalence of del(GJB6-D13S1830) in our population.
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Affiliation(s)
- Mediha Trabelsi
- Charles Nicolle Hospital, Congenital and Hereditary Diseases, Tunis, Tunisia.
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Babanejad M, Fattahi Z, Bazazzadegan N, Nishimura C, Meyer N, Nikzat N, Sohrabi E, Najmabadi A, Jamali P, Habibi F, Smith RJH, Kahrizi K, Najmabadi H. A comprehensive study to determine heterogeneity of autosomal recessive nonsyndromic hearing loss in Iran. Am J Med Genet A 2012; 158A:2485-92. [PMID: 22903915 DOI: 10.1002/ajmg.a.35572] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 06/23/2012] [Indexed: 11/05/2022]
Abstract
Hearing loss is the most common sensory disorder worldwide and affects 1 of every 500 newborns. In developed countries, at least 50% of cases are genetic, most often resulting in nonsyndromic deafness (70%), which is usually autosomal recessive (∼80%). Although the cause of hearing loss is heterogeneous, mutations in GJB2 gene at DFNB1 locus are the major cause of autosomal recessive nonsyndromic hearing loss (ARNSHL) in many populations. Our previous study showed that mutations of GJB2 gene do not contribute to the major genetic load of deafness in the Iranian population (∼16%). Therefore, to define the importance of other genes in contributing to an ARNSHL phenotype in the Iranian population, we used homozygosity mapping to identify regions of autozygosity-by-descent in 144 families which two or more progeny had ARNSHL but were negative for GJB2 gene mutations. Using flanking or intragenic short-tandem repeat markers for 33 loci we identified 33 different homozygous variations in 10 genes, of which 9 are novel. In aggregate, these data explain ∼40% of genetic background of ARNHSL in the Iranian population.
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Affiliation(s)
- Mojgan Babanejad
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
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Wei X, Sun Y, Xie J, Shi Q, Qu N, Yang G, Cai J, Yang Y, Liang Y, Wang W, Yi X. Next-generation sequencing identifies a novel compound heterozygous mutation in MYO7A in a Chinese patient with Usher Syndrome 1B. Clin Chim Acta 2012; 413:1866-71. [PMID: 22898263 DOI: 10.1016/j.cca.2012.07.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 07/27/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Targeted enrichment and next-generation sequencing (NGS) have been employed for detection of genetic diseases. The purpose of this study was to validate the accuracy and sensitivity of our method for comprehensive mutation detection of hereditary hearing loss, and identify inherited mutations involved in human deafness accurately and economically. METHODS To make genetic diagnosis of hereditary hearing loss simple and timesaving, we designed a 0.60 MB array-based chip containing 69 nuclear genes and mitochondrial genome responsible for human deafness and conducted NGS toward ten patients with five known mutations and a Chinese family with hearing loss (never genetically investigated). RESULTS Ten patients with five known mutations were sequenced using next-generation sequencing to validate the sensitivity of the method. We identified four known mutations in two nuclear deafness causing genes (GJB2 and SLC26A4), one in mitochondrial DNA. We then performed this method to analyze the variants in a Chinese family with hearing loss and identified compound heterozygosity for two novel mutations in gene MYO7A. CONCLUSIONS The compound heterozygosity identified in gene MYO7A causes Usher Syndrome 1B with severe phenotypes. The results support that the combination of enrichment of targeted genes and next-generation sequencing is a valuable molecular diagnostic tool for hereditary deafness and suitable for clinical application.
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Bazazzadegan N, Nikzat N, Fattahi Z, Nishimura C, Meyer N, Sahraian S, Jamali P, Babanejad M, Kashef A, Yazdan H, Sabbagh Kermani F, Taghdiri M, Azadeh B, Mojahedi F, Khoshaeen A, Habibi H, Reyhanifar F, Nouri N, Smith RJH, Kahrizi K, Najmabadi H. The spectrum of GJB2 mutations in the Iranian population with non-syndromic hearing loss--a twelve year study. Int J Pediatr Otorhinolaryngol 2012; 76:1164-74. [PMID: 22695344 DOI: 10.1016/j.ijporl.2012.04.026] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Revised: 04/25/2012] [Accepted: 04/27/2012] [Indexed: 10/28/2022]
Abstract
OBJECTIVE Mutations in GJB2, encoding connexin 26 (CX26), are causally related to autosomal recessive form of non-syndromic hearing loss (NSHL) at the DFNB1 locus and autosomal dominant NSHL at the DFNA3 locus. In this study, we investigated the prevalence of GJB2 mutations in the Iranian deaf population. METHODS A total of 2322 deaf probands presenting the ethnically diverse Iranian population were screened for variants in GJB2. All persons were first screened for the c.35delG mutation, as this variant is the most prevalent GJB2-deafness causing mutation in the Iranian population. In all persons carrying zero or one c.35delG allele, exons 1 and 2 were then sequenced. RESULTS In total, 374 (~16%) families segregated GJB2-related deafness caused by 45 different mutations and 5 novel variants. The c.35delG mutation was most commonly identified and accounts for ~65% of the GJB2 mutations found in population studied. CONCLUSION Our data also show that there is a gradual decrease in the frequency of the c.35delG mutation and of GJB2-related deafness in general in a cline across Iran extending from the northwest to southeast.
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Affiliation(s)
- Niloofar Bazazzadegan
- Genetics Research Centre, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
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