title: Prevalence of mitochondrial DNA mutations in sporadic patients with nonsyndromic sensorineural hearing loss.
abstract: BACKGROUND
  Several mitochondrial DNA mutations have been reported to be associated with nonsyndromic hearing loss in several families. However, little is known about the prevalence of these mutations in sporadic patients with nonsyndromic sensorineural hearing loss.
  
  
  OBJECTIVE
  The purpose of our study was to investigate the incidence of these mitochondrial DNA mutations in such population.
  
  
  METHODS
  A total of 178 sporadic patients with nonsyndromic sensorineural hearing loss were enrolled in this study. Genomic DNA was extracted from the peripheral blood sample. We employed the SNaPshot(®) sequencing method to detect five mitochondrial DNA mutations, including A1555G and A827G in 12S rRNA gene and A7445G, 7472insC, and T7511C in tRNA(Ser(UCN)) gene. Meanwhile, we used polymerase chain reaction and sequenced the products to screen GJB2 gene mutations in patients carrying mitochondrial DNA mutations.
  
  
  RESULTS
  We failed to detect the presence of A1555G mutation in 12S rRNA gene, and of A7445G, 7472insC, T7511C mutations in tRNA(Ser(UCN)) gene in our population. However, we found that 6 patients (3.37%) were carriers of a homozygous A827G mutation and one of them also carried homozygous GJB2 235delC mutation.
  
  
  CONCLUSIONS
  Our findings in the present study indicate that even in sporadic patients with nonsyndromic sensorineural hearing loss, mitochondrial DNA mutations might also contribute to the clinical phenotype.
authors.affiliation: Department of Otolaryngology, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Department of Otolaryngology, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Otolaryngology, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Otolaryngology, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang, China.
authors.forename: Peng-Fang
authors.initials: PF
authors.lastname: Lin
authors.affiliation: Department of Otolaryngology, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang, China.
authors.forename: Jian-Guo
authors.initials: JG
authors.lastname: He
authors.affiliation: Department of Otolaryngology, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang, China. Electronic address: yangbb1959@sina.com.
authors.forename: Bei-Bei
authors.initials: BB
authors.lastname: Yang
mesh_terms: D000293:Adolescent; D000328:Adult; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction; D015995:Prevalence; D012335:RNA, Ribosomal / Q000235:genetics*; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D004272:DNA, Mitochondrial; D012335:RNA, Ribosomal; C075526:RNA, ribosomal, 12S
keywords: Deficiência auditiva; Hearing loss; Mitochondria; Mitocôndrias; rRNA; tRNA