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Fu Y, Huang S, Gao X, Han M, Wang G, Kang D, Yuan Y, Dai P. Analysis of the genotype–phenotype correlation of MYO15A variants in Chinese non-syndromic hearing loss patients. BMC Med Genomics 2022; 15:71. [PMID: 35346193 PMCID: PMC8962197 DOI: 10.1186/s12920-022-01201-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 02/28/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Mutations in the MYO15A gene are a widely recognized cause of autosomal recessive non-syndromic sensorineural hearing loss (NSHL) globally. Here, we examined the role and the genotype–phenotype correlation of MYO15A variants in a cohort of Chinese NSHL cases.
Methods
Eighty-one cases with evidenced MYO15A variants from the 2263 Chinese NSHL cases, who underwent next-generation sequencing (NGS), were enrolled in the study. We investigated the association of MYO15A variants with the severity, progression and age of onset of hearing loss, as well as compared it to the previous reports in different nationalities. The cases were divided into groups according to the number of truncating variants: 2 truncating, 1 truncating and 1 non-truncating, 2 non-truncating variants, and compared the severity of HL among the groups.
Results
MYO15A accounted for 3.58% (81/2263) of all NSHL cases. We analyzed 81 MYO15A-related NSHL cases, 73 of whom were with congenital bilateral, symmetric or severe-to-profound hearing loss (HL), however, 2 of them had a postlingual, asymmetric, mild or moderate HL. There were 102 variants identified in all MYO15A structural domains, 76.47% (78/102) of whom were novel. The most common types of detected variants were missense (44/102, 43.14%), followed by frameshift (27/102, 26.47%), nonsense (14/102, 13.72%), splice site (10/102, 9.80%), in frame (4/102, 3.92%), non-coding (2/102, 1.96%) and synonymous (1/102, 0.98%). The most recurrent variant c.10245_10247delCTC was detected in 12 cases. We observed that the MYO15A variants, located in its N-terminal, motor and FERM domains, led to partial deafness with better residual hearing at low frequencies. There were 34 cases with biallelic truncating variants, 37 cases with monoallelic truncating variants, and 13 cases with biallelic non-truncating variants. The biallelic non-truncating variants group had the least number of cases (12/81), and most of them (10/12) were with profound NSHL.
Conclusions
MYO15A is a major gene responsible for NSHL in China. Cases with MYO15A variants mostly showed early-onset, symmetric, severe-to-profound hearing loss. This study is by far the largest focused on the evaluation of the genotype–phenotype correlations among the variants in the MYO15A gene and its implication in the outcome of NSHL. The biallelic non-truncating MYO15A variants commonly caused profound HL, and the cases with one or two truncating MYO15A variants tended to increase the risk of HL. Nevertheless, further investigations are needed to clarify the causes for the variable severities and progression rates of hearing loss and the detected MYO15A variants in these cases.
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Characterization of a novel MYO3A missense mutation associated with a dominant form of late onset hearing loss. Sci Rep 2018; 8:8706. [PMID: 29880844 PMCID: PMC5992146 DOI: 10.1038/s41598-018-26818-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 05/18/2018] [Indexed: 01/08/2023] Open
Abstract
Whole-exome sequencing of samples from affected members of two unrelated families with late-onset non-syndromic hearing loss revealed a novel mutation (c.2090 T > G; NM_017433) in MYO3A. The mutation was confirmed in 36 affected individuals, showing autosomal dominant inheritance. The mutation alters a single residue (L697W or p.Leu697Trp) in the motor domain of the stereocilia protein MYO3A, leading to a reduction in ATPase activity, motility, and an increase in actin affinity. MYO3A-L697W showed reduced filopodial actin protrusion initiation in COS7 cells, and a predominant tipward accumulation at filopodia and stereocilia when coexpressed with wild-type MYO3A and espin-1, an actin-regulatory MYO3A cargo. The combined higher actin affinity and duty ratio of the mutant myosin cause increased retention time at stereocilia tips, resulting in the displacement of the wild-type MYO3A protein, which may impact cargo transport, stereocilia length, and mechanotransduction. The dominant negative effect of the altered myosin function explains the dominant inheritance of deafness.
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Rudman JR, Kabahuma RI, Bressler SE, Feng Y, Blanton SH, Yan D, Liu XZ. The genetic basis of deafness in populations of African descent. J Genet Genomics 2017; 44:285-294. [PMID: 28642064 DOI: 10.1016/j.jgg.2017.03.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/03/2017] [Accepted: 03/24/2017] [Indexed: 11/24/2022]
Abstract
Hearing loss is the most common sensorineural disorder worldwide and is associated with more than 1000 mutations in more than 90 genes. While mutations in genes such as GJB2 (gap-junction protein β 2) and GJB6 (gap-junction protein β 6) are highly prevalent in Caucasian, Asian, and Middle Eastern populations, they are rare in both native African populations and those of African descent. The objective of this paper is to review the current knowledge regarding the epidemiology and genetics of hearing loss in African populations with a focus on native sub-Saharan African populations. Environmental etiologies related to poor access to healthcare and perinatal care account for the majority of cases. Syndromic etiologies including Waardenburg, Pendred and Usher syndromes are uncommon causes of hearing loss in these populations. Of the non-syndromic causes, common mutations in GJB2 and GJB6 are rarely implicated in populations of African descent. Recent use of next-generation sequencing (NGS) has identified several candidate deafness genes in African populations from Nigeria and South Africa that are unique when compared to common causative mutations worldwide. Researchers also recently described a dominant mutation in MYO3a in an African American family with non-syndromic hearing loss. The use of NGS and specialized panels will aid in identifying rare and novel mutations in a more cost- and time-effective manner. The identification of common hearing loss mutations in indigenous African populations will pave the way for translation into genetic deafness research in populations of African descent worldwide.
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Affiliation(s)
- Jason R Rudman
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Rosemary I Kabahuma
- Department of Otorhinolaryngology, Steve Biko Academic Hospital, University of Pretoria, Pretoria 0001, South Africa.
| | - Sara E Bressler
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Yong Feng
- Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Susan H Blanton
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA; John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Denise Yan
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Xue-Zhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha 410008, China; Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA; John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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Kosyakov SY, Kirdeeva AI. [The etiopathogenetic aspects of idiopathic sensorineural impairment of hearing]. Vestn Otorinolaringol 2017; 82:95-101. [PMID: 28514375 DOI: 10.17116/otorino201681695-101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The objectives of the present work were the overview of the results of the modern investigations concerning etiology of idiopathic sensorineural impairment of hearing as well as the analysis of the theory of microthrombus formation and its role in pathogenesis of hearing impairment.
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Affiliation(s)
- S Ya Kosyakov
- Russian Medical Academy for Post-Graduate Education, Moscow, Russia, 125993
| | - A I Kirdeeva
- Russian Medical Academy for Post-Graduate Education, Moscow, Russia, 125993
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Tang HY, Fang P, Lin JW, Darilek S, Osborne BT, Haymond JA, Manolidis S, Roa BB, Oghalai JS, Alford RL. DNA sequence analysis and genotype-phenotype assessment in 71 patients with syndromic hearing loss or auditory neuropathy. BMJ Open 2015; 5:e007506. [PMID: 25991456 PMCID: PMC4442153 DOI: 10.1136/bmjopen-2014-007506] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVES Aetiological assessment of 71 probands whose clinical presentation suggested a genetic syndrome or auditory neuropathy. METHODS Sanger sequencing was performed on DNA isolated from peripheral blood or lymphoblastoid cell lines. Genes were selected for sequencing based on each patient's clinical presentation and suspected diagnosis. Observed DNA sequence variations were assessed for pathogenicity by review of the scientific literature, and mutation and polymorphism databases, through the use of in silico tools including sorting intolerant from tolerant (SIFT) and polymorphism phenotyping (PolyPhen), and according to the recommendations of the American College of Medical Genetics and Genomics for the interpretation of DNA sequence variations. Novel DNA sequence variations were sought in controls. RESULTS DNA sequencing of the coding and near-coding regions of genes relevant to each patient's clinical presentation revealed 37 sequence variations of known or uncertain pathogenicity in 9 genes from 25 patients. 14 novel sequence variations were discovered. Assessment of phenotypes revealed notable findings in 9 patients. CONCLUSIONS DNA sequencing in patients whose clinical presentation suggested a genetic syndrome or auditory neuropathy provided opportunities for aetiological assessment and more precise genetic counselling of patients and families. The failure to identify a genetic aetiology in many patients in this study highlights the extreme heterogeneity of genetic hearing loss, the incompleteness of current knowledge of aetiologies of hearing loss, and the limitations of conventional DNA sequencing strategies that evaluate only coding and near-coding segments of genes.
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Affiliation(s)
- Hsiao-Yuan Tang
- Bobby R Alford Department of Otolaryngology—Head and Neck Surgery, Baylor College of Medicine, Houston, Texas, USA
| | - Ping Fang
- Medical Genetics Laboratories, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Jerry W Lin
- Bobby R Alford Department of Otolaryngology—Head and Neck Surgery, Baylor College of Medicine, Houston, Texas, USA
| | - Sandra Darilek
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Brooke T Osborne
- Bobby R Alford Department of Otolaryngology—Head and Neck Surgery, Baylor College of Medicine, Houston, Texas, USA
| | - Jo Ann Haymond
- Bobby R Alford Department of Otolaryngology—Head and Neck Surgery, Baylor College of Medicine, Houston, Texas, USA
| | - Spiros Manolidis
- Department of Otorhinolaryngology—Head & Neck Surgery, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York, USA
| | | | - John S Oghalai
- Department of Otolaryngology—Head and Neck Surgery, Stanford University, Stanford, California, USA
| | - Raye L Alford
- Bobby R Alford Department of Otolaryngology—Head and Neck Surgery, Baylor College of Medicine, Houston, Texas, USA
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Dantas VGL, Lezirovitz K, Yamamoto GL, Moura de Souza CF, Ferreira SG, Mingroni-Netto RC. c.G2114A MYH9 mutation (DFNA17) causes non-syndromic autosomal dominant hearing loss in a Brazilian family. Genet Mol Biol 2014; 37:616-21. [PMID: 25505834 PMCID: PMC4261959 DOI: 10.1590/s1415-47572014005000025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 07/28/2014] [Indexed: 11/22/2022] Open
Abstract
We studied a family presenting 10 individuals affected by autosomal dominant deafness in all frequencies and three individuals affected by high frequency hearing loss. Genomic scanning using the 50k Affymetrix microarray technology yielded a Lod Score of 2.1 in chromosome 14 and a Lod Score of 1.9 in chromosome 22. Mapping refinement using microsatellites placed the chromosome 14 candidate region between markers D14S288 and D14S276 (8.85 cM) and the chromosome 22 near marker D22S283. Exome sequencing identified two candidate variants to explain hearing loss in chromosome 14 [PTGDR – c.G894A:p.R298R and PTGER2 – c.T247G:p.C83G], and one in chromosome 22 [MYH9, c.G2114A:p.R705H]. Pedigree segregation analysis allowed exclusion of the PTGDR and PTGER2 variants as the cause of deafness. However, the MYH9 variant segregated with the phenotype in all affected members, except the three individuals with different phenotype. This gene has been previously described as mutated in autosomal dominant hereditary hearing loss and corresponds to DFNA17. The mutation identified in our study is the same described in the prior report. Thus, although linkage studies suggested a candidate gene in chromosome 14, we concluded that the mutation in chromosome 22 better explains the hearing loss phenotype in the Brazilian family.
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Affiliation(s)
- Vitor G L Dantas
- Departamento de Genetica e Biologia Evolutiva , Instituto de Biociências , Instituto de Biociências , Universidade de São Paulo , São Paulo, SP , Brazil
| | - Karina Lezirovitz
- Departamento de Genetica e Biologia Evolutiva , Instituto de Biociências , Instituto de Biociências , Universidade de São Paulo , São Paulo, SP , Brazil . ; Laboratório de Otorrinolaringologia/LIM32 , Hospital das Clinicas , Faculdade de Medicina , Universidade de São Paulo , São Paulo, SP , Brazil
| | - Guilherme L Yamamoto
- Departamento de Genetica e Biologia Evolutiva , Instituto de Biociências , Instituto de Biociências , Universidade de São Paulo , São Paulo, SP , Brazil
| | | | - Simone Gomes Ferreira
- Departamento de Genetica e Biologia Evolutiva , Instituto de Biociências , Instituto de Biociências , Universidade de São Paulo , São Paulo, SP , Brazil
| | - Regina C Mingroni-Netto
- Departamento de Genetica e Biologia Evolutiva , Instituto de Biociências , Instituto de Biociências , Universidade de São Paulo , São Paulo, SP , Brazil
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Kim HJ, Won HH, Park KJ, Hong SH, Ki CS, Cho SS, Venselaar H, Vriend G, Kim JW. SNP linkage analysis and whole exome sequencing identify a novel POU4F3 mutation in autosomal dominant late-onset nonsyndromic hearing loss (DFNA15). PLoS One 2013; 8:e79063. [PMID: 24260153 PMCID: PMC3832514 DOI: 10.1371/journal.pone.0079063] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 09/24/2013] [Indexed: 11/18/2022] Open
Abstract
Autosomal dominant non-syndromic hearing loss (AD-NSHL) is one of the most common genetic diseases in human and is well-known for the considerable genetic heterogeneity. In this study, we utilized whole exome sequencing (WES) and linkage analysis for direct genetic diagnosis in AD-NSHL. The Korean family had typical AD-NSHL running over 6 generations. Linkage analysis was performed by using genome-wide single nucleotide polymorphism (SNP) chip and pinpointed a genomic region on 5q31 with a significant linkage signal. Sequential filtering of variants obtained from WES, application of the linkage region, bioinformatic analyses, and Sanger sequencing validation identified a novel missense mutation Arg326Lys (c.977G>A) in the POU homeodomain of the POU4F3 gene as the candidate disease-causing mutation in the family. POU4F3 is a known disease gene causing AD-HSLH (DFNA15) described in 5 unrelated families until now each with a unique mutation. Arg326Lys was the first missense mutation affecting the 3(rd) alpha helix of the POU homeodomain harboring a bipartite nuclear localization signal sequence. The phenotype findings in our family further supported previously noted intrafamilial and interfamilial variability of DFNA15. This study demonstrated that WES in combination with linkage analysis utilizing bi-allelic SNP markers successfully identified the disease locus and causative mutation in AD-NSHL.
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Affiliation(s)
- Hee-Jin Kim
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hong-Hee Won
- Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Korea
| | - Kyoung-Jin Park
- Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Korea
| | - Sung Hwa Hong
- Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Chang-Seok Ki
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Sang Sun Cho
- Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Korea
| | - Hanka Venselaar
- Centre for Molecular and Biomolecular Informatics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Gert Vriend
- Centre for Molecular and Biomolecular Informatics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Jong-Won Kim
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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Expression of deafness protein Tmie in postnatal developmental stages of C57BL/6J mice. Lab Anim Res 2012; 28:147-50. [PMID: 22787490 PMCID: PMC3389840 DOI: 10.5625/lar.2012.28.2.147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 06/08/2012] [Accepted: 06/11/2012] [Indexed: 11/29/2022] Open
Abstract
Loss-of function mutations in the transmembrane inner ear expressed (Tmie/TMIE) gene have been shown to cause deafness in mice and humans (DFNB6). Previous studies report that the circling mouse can be an animal model for DFNB6. However, the expression pattern of Tmie protein in postnatal developmental stages has not been clearly revealed. In this study we tried to investigate the expression of Tmie protein in the liver, spleen, kidney, and lung, as well as in the cochlea. We examined various tissue samples from five different age groups of C57BL/6J animals. Using western blotting analysis, the expression of Tmie protein in these organs has been identified. The results show that Tmie protein expression in the cochlea has been increased in postnatal developmental stages, indicating that Tmie plays an important role in not only the development and also in the function of the cochlea. The expression pattern of Tmie in adult mouse organs such as the liver, spleen, kidney, and spleen significantly vary in adult rats. The order of Tmie expression level in mice (63 days after birth) was spleen, liver, lung, cochlea, and kidney, whereas in the adult rat it was liver, cochlea, lung, spleen, and kidney.
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Kabahuma RI, Ouyang X, Du LL, Yan D, Hutchin T, Ramsay M, Penn C, Liu XZ. Absence of GJB2 gene mutations, the GJB6 deletion (GJB6-D13S1830) and four common mitochondrial mutations in nonsyndromic genetic hearing loss in a South African population. Int J Pediatr Otorhinolaryngol 2011; 75:611-7. [PMID: 21392827 PMCID: PMC4303037 DOI: 10.1016/j.ijporl.2011.01.029] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 01/19/2011] [Accepted: 01/21/2011] [Indexed: 10/18/2022]
Abstract
OBJECTIVE The purpose of this study was to determine the prevalence of mutations in the GJB2 gene, the GJB6-D13S1830 deletion and the four common mitochondrial mutations (A1555G, A3243G, A7511C and A7445G) in a South African population. METHODS Using single-strand conformation polymorphism and direct sequencing for screening GJB2 mutation; Multiplex PCR Amplification for GJB6-D13S1830 deletion and Restriction Fragment-Length Polymorphism (PCR-RFLP) analysis for the four common mtDNA mutations. We screened 182 hearing impaired students to determine the frequency of these mutations in the population. RESULTS None of the reported disease causing mutations in GJB2 nor any novel pathogenic mutations in the coding region were detected, in contrast to the findings among Caucasians. The GJB6-D13S1830 deletion and the mitochondrial mutations were not observed in this group. CONCLUSION These results suggest that GJB2 may not be a significant deafness gene among sub-Saharan Africans, pointing to other unidentified genes as responsible for nonsyndromic hearing loss in these populations.
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Affiliation(s)
- Rosemary I. Kabahuma
- Department of Speech Pathology and Audiology, University of Witwatersrand, Johannesburg, South Africa,Division of Human Genetics, National Health Laboratory Service and School of Pathology, University of Witwatersrand, Johannesburg, South Africa,Department of Otorhinolaryngology, Polokwane/Mankweng Hospital Complex, Polokwane, Limpopo Province, South Africa
| | - Xiaomei Ouyang
- Department of Otolaryngology, University of Miami, Miami, FL, USA
| | - Li Lin Du
- Department of Otolaryngology, University of Miami, Miami, FL, USA
| | - Denise Yan
- Department of Otolaryngology, University of Miami, Miami, FL, USA
| | - Tim Hutchin
- Birmingham Children’s Hospital, Birmingham, UK
| | - Michele Ramsay
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, University of Witwatersrand, Johannesburg, South Africa,Corresponding author at: Division of Human Genetics, National Health Laboratory Service and School of Pathology, University of Witwatersrand, PO Box 1038, Johannesburg 2000, South Africa. Tel.: +27 011 489 9214; fax: +27 011 498 9226. (M. Ramsay)
| | - Claire Penn
- Department of Speech Pathology and Audiology, University of Witwatersrand, Johannesburg, South Africa
| | - Xue-Zhong Liu
- Department of Otolaryngology, University of Miami, Miami, FL, USA,Corresponding author at: Department of Otolaryngology (D-48), University of Miami, 1666 NW 12th Avenue, Miami, FL 33136, USA. Tel.: +1 305 243 5695; fax: +1 305 243 4925. (X.-Z. Liu)
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Abstract
It has been argued by some authors that our reaction to deaf parents who choose deafness for their children ought to be compassion, not condemnation. Although I agree with the reasoning proposed I suggest that this practice could be regarded as unethical. In this article, I shall use the term "dysgenic" as a culturally imposed genetic selection not to achieve any improvement of the human person but to select genetic traits that are commonly accepted as a disabling condition by the majority of the social matrix; in short as a handicap. As in eugenics, dysgenics can be achieved in a positive and a negative way. Positive dysgenics intends to increase the overall number of people with a particular genetic trait. Marriage between deaf people or conceiving deaf children through reproductive technology are examples of positive dysgenics. Negative dysgenics can be obtained through careful prenatal or pre-implantation selection and abortion (or discarding) of normal embryos and foetuses. Only deaf children would be allowed to live. If dysgenics is seen as a programmed genetic intervention that undesirably shapes the human condition--like deliberately creating deaf or dwarf people--the professionals involved in reproductive technologies should answer the question if this should be an accepted ethical practice because the basic human right to an open future is violated.
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Affiliation(s)
- Rui Nunes
- Department of Bioethics of the School of Medicine, University of Oporto, Estrada da Circunvalação 9925, Porto, EU, 4250-150, Portugal.
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Rendtorff ND, Frödin M, Attié-Bitach T, Vekemans M, Tommerup N. Identification and characterization of an inner ear-expressed human melanoma inhibitory activity (MIA)-like gene (MIAL) with a frequent polymorphism that abolishes translation. Genomics 2001; 71:40-52. [PMID: 11161796 DOI: 10.1006/geno.2000.6409] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To discover new cochlea-specific genes as candidate genes for nonsyndromic hearing impairment, we searched in The Institute of Genome Research database for expressed sequence tags isolated from the cochlea only. This led to the cloning and characterization of a human gene named melanoma inhibitory activity-like (MIAL; HGMW-approved symbol OTOR alias MIAL) gene. In situ hybridization revealed MIAL expression in a cell layer beneath the sensory epithelium of cochlea and vestibule of human fetal inner ear. No other human tissue, except fetal brain, showed expression of MIAL when analyzed by in situ hybridization or reverse transcription-polymerase chain reaction. The cDNA of the mouse homologue was also cloned and mapped about 80 cM from the top of mouse chromosome 2. In mouse, Mial was also expressed in the cochlea and the vestibule of the inner ear, as well as in brain, eye, limb, and ovary. Expression in mammalian cell cultures showed that MIAL is translated as an approximately 15-kDa polypeptide that is assembled into a covalently linked homodimer, modified by sulfation, and secreted from the cells via the Golgi apparatus. In the human MIAL gene, a frequent polymorphism was discovered in the translation initiation codon (ACG instead of ATG). Of 505 individuals, 48 (9.5%) were ATG/ACG heterozygous and 1 (0.2%) was homozygous for ACG. No MIAL protein was synthesized in cells transfected with cDNA of the ACG allele. The inner ear-restricted expression pattern and the existence of an inactive allele suggest that MIAL may contribute to inner-ear dysfunction in humans.
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MESH Headings
- Alleles
- Amino Acid Sequence
- Animals
- Base Sequence
- Brain/embryology
- Brefeldin A/pharmacology
- COS Cells
- Chromosome Mapping
- Cloning, Molecular
- DNA, Complementary/metabolism
- Databases, Factual
- Ear, Inner/embryology
- Ear, Inner/metabolism
- Electrophoresis, Polyacrylamide Gel
- Expressed Sequence Tags
- Extracellular Matrix Proteins
- Extremities/embryology
- Eye/embryology
- Female
- Humans
- Immunoblotting
- Immunohistochemistry
- In Situ Hybridization
- Mice
- Models, Genetic
- Molecular Sequence Data
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Ovary/embryology
- Polymorphism, Genetic
- Precipitin Tests
- Protein Biosynthesis
- Protein Processing, Post-Translational
- Protein Synthesis Inhibitors/pharmacology
- Proteins/genetics
- Proteins/physiology
- RNA, Messenger/metabolism
- Radiation Hybrid Mapping
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Amino Acid
- Tissue Distribution
- Transfection
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Affiliation(s)
- N D Rendtorff
- Department of Medical Genetics, Institute of Medical Biochemistry and Genetics, University of Copenhagen, N, 2200, Denmark
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