title: Analysis of mitochondrial alterations in Brazilian patients with sensorineural hearing loss using MALDI-TOF mass spectrometry.
abstract: Mutations in the mitochondrial DNA (mtDNA) have been associated with aminoglycoside-induced and nonsyndromic deafness in different populations. In the present study, we investigated the contribution of mutations in mitochondrial genes to the etiology of hearing loss in a Brazilian sample.
  
  
  
  Using mass spectrometry genotyping technology, combined with direct sequencing, 50 alterations previously described in 14 mitochondrial genes were screened in 152 patients with sensorineural hearing loss and in104 normal hearing controls.
  
  
  
  Fifteen known mitochondrial alterations were detected (G709A, A735G, A827G, G988A, A1555G, T4363C, T5628C, T5655C, G5821A, C7462T, G8363A, T10454C, G12236A, T1291C, G15927A). Pathogenic mutations in MT-RNR1 and MT-TK genes were detected in 3 % (5/152) of the patients with hearing loss.
  
  
  
  This study contributed to show the spectrum of mitochondrial variants in Brazilian patients with hearing loss. Frequency of A1555G was relatively high (2.6 %), indicating that this mutation is an important cause of hearing loss in our population. This work reports for the first time the investigation and the detection of the tRNA(Lys) G8363A mutation in Brazilian patients with maternally inherited sensorineural hearing loss.
authors.affiliation: Center for Molecular and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Cidade Universitária Zeferino Vaz, Avenida Cândido Rondon 400, PO Box 6010, 13083-875, Campinas, São Paulo, Brazil.
authors.forename: Rogério Marins
authors.initials: RM
authors.lastname: Alves
authors.affiliation: Center for Molecular and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Cidade Universitária Zeferino Vaz, Avenida Cândido Rondon 400, PO Box 6010, 13083-875, Campinas, São Paulo, Brazil.
authors.forename: Sueli Matilde
authors.initials: SM
authors.lastname: da Silva Costa
authors.affiliation: Center for Molecular and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Cidade Universitária Zeferino Vaz, Avenida Cândido Rondon 400, PO Box 6010, 13083-875, Campinas, São Paulo, Brazil.
authors.forename: Paulo Mauricio
authors.initials: PM
authors.lastname: do Amôr Divino Miranda
authors.affiliation: Center for Molecular and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Cidade Universitária Zeferino Vaz, Avenida Cândido Rondon 400, PO Box 6010, 13083-875, Campinas, São Paulo, Brazil.
authors.forename: Priscila Zonzini
authors.initials: PZ
authors.lastname: Ramos
authors.affiliation: Center for Molecular and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Cidade Universitária Zeferino Vaz, Avenida Cândido Rondon 400, PO Box 6010, 13083-875, Campinas, São Paulo, Brazil.
authors.forename: Thiago Gibbin
authors.initials: TG
authors.lastname: Marconi
authors.affiliation: Center for Molecular and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Cidade Universitária Zeferino Vaz, Avenida Cândido Rondon 400, PO Box 6010, 13083-875, Campinas, São Paulo, Brazil.
authors.forename: Gisele
authors.initials: G
authors.lastname: Santos Oliveira
authors.affiliation: Otology, Audiology and Implantable Ear Prostheses, University of Campinas (UNICAMP), Cidade Universitária Zeferino Vaz, Campinas, São Paulo, Brazil.
authors.forename: Arthur Menino
authors.initials: AM
authors.lastname: Castilho
authors.affiliation: Center for Molecular and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Cidade Universitária Zeferino Vaz, Avenida Cândido Rondon 400, PO Box 6010, 13083-875, Campinas, São Paulo, Brazil. sartor@unicamp.br.
authors.forename: Edi Lúcia
authors.initials: EL
authors.lastname: Sartorato
mesh_terms: D001938:Brazil; D016022:Case-Control Studies; D004272:DNA, Mitochondrial / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D005260:Female; D005838:Genotype; D006319:Hearing Loss, Sensorineural / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000235:genetics*; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2 / Q000235:genetics; D012357:RNA, Transfer, Lys / Q000235:genetics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D004272:DNA, Mitochondrial; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D012357:RNA, Transfer, Lys
keywords: Hearing loss; Molecular diagnosis; mt-DNA mutations