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Hearing Disorders: HELP
Articles by Niloofar Bazazzadegan
Based on 11 articles published since 2010
(Why 11 articles?)
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Between 2010 and 2020, Niloofar Bazazzadegan wrote the following 11 articles about Hearing Disorders.
 
+ Citations + Abstracts
1 Review Heterogeneity of Hereditary Hearing Loss in Iran: a Comprehensive Review. 2016

Beheshtian, Maryam / Babanejad, Mojgan / Azaiez, Hela / Bazazzadegan, Niloofar / Kolbe, Diana / Sloan-Heggen, Christina / Arzhangi, Sanaz / Booth, Kevin / Mohseni, Marzieh / Frees, Kathy / Azizi, Mohammad Hossein / Daneshi, Ahmad / Farhadi, Mohammad / Kahrizi, Kimia / Smith, Richard Jh / Najmabadi, Hossein. ·Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. · Department of Otolaryngology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA. · Academy of Medical Sciences Islamic Republic of Iran, Tehran, Iran. · Head and Neck Surgery Department and Research Center, Iran University of Medical Sciences, Tehran, Iran. ·Arch Iran Med · Pubmed #27743438.

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.

2 Review Two Iranian families with a novel mutation in GJB2 causing autosomal dominant nonsyndromic hearing loss. 2011

Bazazzadegan, Niloofar / Sheffield, Abraham M / Sobhani, Masoomeh / Kahrizi, Kimia / Meyer, Nicole C / Van Camp, Guy / Hilgert, Nele / Abedini, Seyedeh Sedigheh / Habibi, Farkhondeh / Daneshi, Ahmad / Nishimura, Carla / Avenarius, Matthew R / Farhadi, Mohammad / Smith, Richard J H / Najmabadi, Hossein. ·Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. ·Am J Med Genet A · Pubmed #21484990.

ABSTRACT: Mutations in GJB2, encoding connexin 26 (Cx26), cause both autosomal dominant and autosomal recessive nonsyndromic hearing loss (ARNSHL) at the DFNA3 and DFNB1 loci, respectively. Most of the over 100 described GJB2 mutations cause ARNSHL. Only a minority has been associated with autosomal dominant hearing loss. In this study, we present two families with autosomal dominant nonsyndromic hearing loss caused by a novel mutation in GJB2 (p.Asp46Asn). Both families were ascertained from the same village in northern Iran consistent with a founder effect. This finding implicates the D46N missense mutation in Cx26 as a common cause of deafness in this part of Iran mandating mutation screening of GJB2 for D46N in all persons with hearing loss who originate from this geographic region.

3 Article Characterising the spectrum of autosomal recessive hereditary hearing loss in Iran. 2015

Sloan-Heggen, Christina M / Babanejad, Mojgan / Beheshtian, Maryam / Simpson, Allen C / Booth, Kevin T / Ardalani, Fariba / Frees, Kathy L / Mohseni, Marzieh / Mozafari, Reza / Mehrjoo, Zohreh / Jamali, Leila / Vaziri, Saeideh / Akhtarkhavari, Tara / Bazazzadegan, Niloofar / Nikzat, Nooshin / Arzhangi, Sanaz / Sabbagh, Farahnaz / Otukesh, Hasan / Seifati, Seyed Morteza / Khodaei, Hossein / Taghdiri, Maryam / Meyer, Nicole C / Daneshi, Ahmad / Farhadi, Mohammad / Kahrizi, Kimia / Smith, Richard J H / Azaiez, Hela / Najmabadi, Hossein. ·Molecular Otolaryngology & Renal Research Laboratories, Department of Otolaryngology-Head and Neck Surgery, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA. · Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. · Molecular Otolaryngology & Renal Research Laboratories, Department of Otolaryngology-Head and Neck Surgery, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA. · Genetics Counseling Center, Kerman Welfare Institution, Kerman, Iran. · Division of Pediatric Nephrology, Hazrat-e-Ali Asghar Educational & Treatment Center, Iran University of Medical Sciences, Tehran, Iran. · Meybod Genetics Research Center, Shahid Fiazbakhsh Rehabilitation Comprehensive Center, Welfare Organization, Yazd, Iran. · Genetic Counseling Center, Shiraz Welfare Institution, Shiraz, Iran. · Head and Neck Surgery Department and Research Center, Iran University of Medical Sciences, Tehran, Iran. · Molecular Otolaryngology & Renal Research Laboratories, Department of Otolaryngology-Head and Neck Surgery, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA Interdepartmental PhD Program in Genetics, University of Iowa, Iowa City, Iowa, USA. ·J Med Genet · Pubmed #26445815.

ABSTRACT: BACKGROUND: Countries with culturally accepted consanguinity provide a unique resource for the study of rare recessively inherited genetic diseases. Although hereditary hearing loss (HHL) is not uncommon, it is genetically heterogeneous, with over 85 genes causally implicated in non-syndromic hearing loss (NSHL). This heterogeneity makes many gene-specific types of NSHL exceedingly rare. We sought to define the spectrum of autosomal recessive HHL in Iran by investigating both common and rarely diagnosed deafness-causing genes. DESIGN: Using a custom targeted genomic enrichment (TGE) panel, we simultaneously interrogated all known genetic causes of NSHL in a cohort of 302 GJB2-negative Iranian families. RESULTS: We established a genetic diagnosis for 67% of probands and their families, with over half of all diagnoses attributable to variants in five genes: SLC26A4, MYO15A, MYO7A, CDH23 and PCDH15. As a reflection of the power of consanguinity mapping, 26 genes were identified as causative for NSHL in the Iranian population for the first time. In total, 179 deafness-causing variants were identified in 40 genes in 201 probands, including 110 novel single nucleotide or small insertion-deletion variants and three novel CNV. Several variants represent founder mutations. CONCLUSION: This study attests to the power of TGE and massively parallel sequencing as a diagnostic tool for the evaluation of hearing loss in Iran, and expands on our understanding of the genetics of HHL in this country. Families negative for variants in the genes represented on this panel represent an excellent cohort for novel gene discovery.

4 Article A novel mutation of the USH2C (GPR98) gene in an Iranian family with Usher syndrome type II. 2014

Kahrizi, Kimia / Bazazzadegan, Niloofar / Jamali, Leila / Nikzat, Nooshin / Kashef, Atie / Najmabadi, Hossein. ·Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran 1985713834, Iran. hnajm12@yahoo.com. ·J Genet · Pubmed #25572244.

ABSTRACT: -- No abstract --

5 Article Utilizing ethnic-specific differences in minor allele frequency to recategorize reported pathogenic deafness variants. 2014

Shearer, A Eliot / Eppsteiner, Robert W / Booth, Kevin T / Ephraim, Sean S / Gurrola, José / Simpson, Allen / Black-Ziegelbein, E Ann / Joshi, Swati / Ravi, Harini / Giuffre, Angelica C / Happe, Scott / Hildebrand, Michael S / Azaiez, Hela / Bayazit, Yildirim A / Erdal, Mehmet Emin / Lopez-Escamez, Jose A / Gazquez, Irene / Tamayo, Marta L / Gelvez, Nancy Y / Leal, Greizy Lopez / Jalas, Chaim / Ekstein, Josef / Yang, Tao / Usami, Shin-ichi / Kahrizi, Kimia / Bazazzadegan, Niloofar / Najmabadi, Hossein / Scheetz, Todd E / Braun, Terry A / Casavant, Thomas L / LeProust, Emily M / Smith, Richard J H. ·Molecular Otolaryngology & Renal Research Labs, Department of Otolaryngology-Head and Neck Surgery, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA. · Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA. · Agilent Technologies, Cedar Creek, TX 78612, USA. · Epilepsy Research Centre, Department of Medicine, University of Melbourne, Heidelberg, VIC 3084, Australia. · Department of Otolaryngology, Faculty of Medicine, Medipol University, Istanbul 34083, Turkey. · Department of Medical Biology and Genetics, University of Mersin, Mersin 33160, Turkey. · Otology and Neurotology Group CTS495, Center for Genomic and Oncological Research (GENyO), Granada 18012, Spain. · Instituto de Genética Humana, Pontificia Universidad Javeriana, Bogotá 11001000, Colombia. · Bonei Olam, Center for Rare Jewish Genetic Disorders, Brooklyn, NY 11204, USA. · Dor Yeshorim, The Committee for Prevention of Jewish Genetic Diseases, Brooklyn, NY 11211, USA. · Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, and the Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai 20025, China. · Department of Otorhinolaryngology, School of Medicine, Shinshu University, Matsumoto, Nagano 390-8621, Japan. · Genetics Research Centre, University of Social Welfare and Rehabilitation Sciences, Tehran 1985713834, Iran. · Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA; Center for Bioinformatics and Computational Biology, University of Iowa, Iowa City, IA 52242, USA; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA 52242, USA. · Molecular Otolaryngology & Renal Research Labs, Department of Otolaryngology-Head and Neck Surgery, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Interdepartmental PhD Program in Genetics, University of Iowa, Iowa City, IA 52242, USA; Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA. Electronic address: richard-smith@uiowa.edu. ·Am J Hum Genet · Pubmed #25262649.

ABSTRACT: Ethnic-specific differences in minor allele frequency impact variant categorization for genetic screening of nonsyndromic hearing loss (NSHL) and other genetic disorders. We sought to evaluate all previously reported pathogenic NSHL variants in the context of a large number of controls from ethnically distinct populations sequenced with orthogonal massively parallel sequencing methods. We used HGMD, ClinVar, and dbSNP to generate a comprehensive list of reported pathogenic NSHL variants and re-evaluated these variants in the context of 8,595 individuals from 12 populations and 6 ethnically distinct major human evolutionary phylogenetic groups from three sources (Exome Variant Server, 1000 Genomes project, and a control set of individuals created for this study, the OtoDB). Of the 2,197 reported pathogenic deafness variants, 325 (14.8%) were present in at least one of the 8,595 controls, indicating a minor allele frequency (MAF) > 0.00006. MAFs ranged as high as 0.72, a level incompatible with pathogenicity for a fully penetrant disease like NSHL. Based on these data, we established MAF thresholds of 0.005 for autosomal-recessive variants (excluding specific variants in GJB2) and 0.0005 for autosomal-dominant variants. Using these thresholds, we recategorized 93 (4.2%) of reported pathogenic variants as benign. Our data show that evaluation of reported pathogenic deafness variants using variant MAFs from multiple distinct ethnicities and sequenced by orthogonal methods provides a powerful filter for determining pathogenicity. The proposed MAF thresholds will facilitate clinical interpretation of variants identified in genetic testing for NSHL. All data are publicly available to facilitate interpretation of genetic variants causing deafness.

6 Article A comprehensive study to determine heterogeneity of autosomal recessive nonsyndromic hearing loss in Iran. 2012

Babanejad, Mojgan / Fattahi, Zohreh / Bazazzadegan, Niloofar / Nishimura, Carla / Meyer, Nicole / Nikzat, Nooshin / Sohrabi, Elahe / Najmabadi, Amin / Jamali, Peyman / Habibi, Farkhonde / Smith, Richard J H / Kahrizi, Kimia / Najmabadi, Hossein. ·Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. ·Am J Med Genet A · Pubmed #22903915.

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.

7 Article Screening for MYO15A gene mutations in autosomal recessive nonsyndromic, GJB2 negative Iranian deaf population. 2012

Fattahi, Zohreh / Shearer, A Eliot / Babanejad, Mojgan / Bazazzadegan, Niloofar / Almadani, Seyed Navid / Nikzat, Nooshin / Jalalvand, Khadijeh / Arzhangi, Sanaz / Esteghamat, Fatemehsadat / Abtahi, Rezvan / Azadeh, Batool / Smith, Richard J H / Kahrizi, Kimia / Najmabadi, Hossein. ·Genetics Research Centre, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. ·Am J Med Genet A · Pubmed #22736430.

ABSTRACT: MYO15A is located at the DFNB3 locus on chromosome 17p11.2, and encodes myosin-XV, an unconventional myosin critical for the formation of stereocilia in hair cells of cochlea. Recessive mutations in this gene lead to profound autosomal recessive nonsyndromic hearing loss (ARNSHL) in humans and the shaker2 (sh2) phenotype in mice. Here, we performed a study on 140 Iranian families in order to determine mutations causing ARNSHL. The families, who were negative for mutations in GJB2, were subjected to linkage analysis. Eight of these families showed linkage to the DFNB3 locus, suggesting a MYO15A mutation frequency of 5.71% in our cohort of Iranian population. Subsequent sequencing of the MYO15A gene led to identification of 7 previously unreported mutations, including 4 missense mutations, 1 nonsense mutation, and 2 deletions in different regions of the myosin-XV protein.

8 Article The spectrum of GJB2 mutations in the Iranian population with non-syndromic hearing loss--a twelve year study. 2012

Bazazzadegan, Niloofar / Nikzat, Nooshin / Fattahi, Zohreh / Nishimura, Carla / Meyer, Nicole / Sahraian, Shima / Jamali, Payman / Babanejad, Mojgan / Kashef, Atie / Yazdan, Hilda / Sabbagh Kermani, Farahnaz / Taghdiri, Maryam / Azadeh, Batool / Mojahedi, Faezeh / Khoshaeen, Atefeh / Habibi, Haleh / Reyhanifar, Farahnaz / Nouri, Narges / Smith, Richard J H / Kahrizi, Kimia / Najmabadi, Hossein. ·Genetics Research Centre, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. ·Int J Pediatr Otorhinolaryngol · Pubmed #22695344.

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.

9 Article Spectrum of GJB2 (Cx26) gene mutations in Iranian Azeri patients with nonsyndromic autosomal recessive hearing loss. 2012

Davarnia, Behzad / Babanejad, Mojgan / Fattahi, Zohreh / Nikzat, Nooshin / Bazazzadegan, Niloofar / Pirzade, Akbar / Farajollahi, Reza / Nishimura, Carla / Jalalvand, Khadijeh / Arzhangi, Sanaz / Kahrizi, Kimia / Smith, Richard J H / Najmabadi, Hossein. ·Genetics Research Centre, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. ·Int J Pediatr Otorhinolaryngol · Pubmed #22172221.

ABSTRACT: OBJECTIVE: Hereditary hearing impairment is a genetically heterogeneous disorder. In spite of this, mutations in the GJB2 gene, encoding connexin 26 (Cx26), are a major cause of nonsyndromic recessive hearing loss in many countries and are largely dependent on ethnic groups. The purpose of our study was to characterize the type and prevalence of GJB2 mutations among Azeri population of Iran. METHODS: Fifty families presenting autosomal recessive nonsyndromic hearing loss from Ardabil province of Iran were studied for mutations in GJB2 gene. All DNA samples were screened for c.35delG mutation by ARMS PCR. Samples from patients who were normal for c.35delG were analyzed for the other variations in GJB2 by direct sequencing. In the absence of mutation detection, GJB6 was screened for the del(GJB6-D13S1830) and del(GJB6-D13S1854). RESULT: Thirteen families demonstrated alteration in the Cx26 (26%). The 35delG mutation was the most common one, accounting for 69.2% (9 out of 13 families). All the detected families were homozygous for this mutation. Two families were homozygous for delE120 and 299-300delAT mutations. We also identified a novel mutation: c.463-464 delTA in 2 families resulting in a frame shift mutation. CONCLUSION: Our results suggest that c.35delG mutation in the GJB2 gene is the most important cause of GJB2 related deafness in Iranian Azeri population.

10 Article Did the GJB2 35delG mutation originate in Iran? 2011

Norouzi, Vahideh / Azizi, Hiva / Fattahi, Zohreh / Esteghamat, Fatemehsadat / Bazazzadegan, Niloofar / Nishimura, Carla / Nikzat, Nooshin / Jalalvand, Khadijeh / Kahrizi, Kimia / Smith, Richard J H / Najmabadi, Hossein. ·Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. ·Am J Med Genet A · Pubmed #21910243.

ABSTRACT: Mutations in GJB2 are a major cause of autosomal recessive non-syndromic hearing loss (ARNSHL) in many populations. A single mutation of this gene (35delG) accounts for approximately 70% of GJB2 mutations that are associated with ARNSHL in Caucasians in many European countries and also in Iranian. In this study, we used PCR and restriction digestion to genotype five single nucleotide polymorphisms (SNPs) that define the genetic background of the 35delG mutation over an interval of 98 Kbp that includes the coding and flanking regions of GJB2. Two microsatellite markers, D13S175 and D13S141, were also analyzed in patients and controls. These data suggest that the 35delG mutation originated in northern Iran.

11 Article Mutations in TMC1 are a common cause of DFNB7/11 hearing loss in the Iranian population. 2010

Hildebrand, Michael S / Kahrizi, Kimia / Bromhead, Catherine J / Shearer, A Eliot / Webster, Jennifer A / Khodaei, Hossein / Abtahi, Rezvan / Bazazzadegan, Niloofar / Babanejad, Mojgan / Nikzat, Nooshin / Kimberling, William J / Stephan, Dietrich / Huygen, Patrick L M / Bahlo, Melanie / Smith, Richard J H / Najmabadi, Hossein. ·Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, USA. ·Ann Otol Rhinol Laryngol · Pubmed #21250555.

ABSTRACT: OBJECTIVES: We investigated the cause of autosomal recessive nonsyndromic hearing loss (ARNSHL) that segregated in 2 consanguineous Iranian families. METHODS: Otologic and audiometric examinations were performed on affected members of each family. Genome-wide parametric multipoint linkage mapping using a recessive model was performed with Affymetrix 50K GeneChips or short tandem repeat polymorphisms. Direct sequencing was used to confirm the causative mutation in each family. RESULTS: In 2 Iranian families, L-1651 and L-8600606, with ARNSHL that mapped to the DFNB7/11 locus, homozygosity for a reported splice site mutation (c.776+1G>A), and a novel deletion (c.1589_1590delCT; p.S530*) were identified in the TMC1 gene, respectively. CONCLUSIONS: Consistent with the previously reported phenotype in DFNB7/11 families, the 2 Iranian families had segregated congenital, profound hearing impairment. However, in family L-1651, one affected family member (IV:3) has milder hearing impairment than expected, suggesting a potential genetic modifier effect. These results indicate that DFNB7/11 is a common form of genetic hearing loss in Iran, because this population is the source of 6 of the 29 TMC1 mutations reported worldwide.