title: GJB2 and mitochondrial 12S rRNA susceptibility mutations in sudden deafness.
abstract: Genetic susceptibility may play an important role in the pathogenesis of sudden deafness. However, the specific genes involved are largely unknown. We sought to explore the frequency of GJB2 and mitochondrial 12S rRNA susceptibility mutations in patients with sudden deafness. Between September 2011 and May 2012, 62 consecutive patients with sudden deafness were seen. In 50 of these, no etiological factors for sudden deafness were found. We detected GJB2 and mitochondrial 12S rRNA variants by direct sequencing in these 50 patients and in 53-aged matched controls with normal hearing. In addition, we undertook functional analyses of the mitochondrial mutations which we detected, applying structural and phylogenetic analysis. GJB2 sequencing identified six mutations, including three pathogenic mutations (c.235delC, c.299-300delAT, c.109G>A) and three polymorphisms, in the study participants, giving an allele frequency of 15.0 %. A homozygous c.109G>A mutation was detected in two participants. A total of 16 variants in mitochondrial 12S rRNA gene were identified in the participants. No significant differences were found in GJB2 heterozygosity or in mitochondrial 12S rRNA variants between patients with sudden deafness and in controls. Our results suggest that the homozygous GJB2 c.109G>A mutation may be a cause of sudden deafness involving both ears. This finding should increase awareness of the likely role of genetic factors in the etiology of sudden deafness in general.
authors.affiliation: Department of Otorhinolaryngology, the First Affiliated Hospital, Sun Yat-Sen University and Institute of Otorhinolaryngology, Sun Yat-sen University, Guangzhou, 510080, People's Republic of China.
authors.forename: Kaitian
authors.initials: K
authors.lastname: Chen
authors.affiliation: Department of Otorhinolaryngology, the First Affiliated Hospital, Sun Yat-Sen University and Institute of Otorhinolaryngology, Sun Yat-sen University, Guangzhou, 510080, People's Republic of China.
authors.forename: Liang
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Otorhinolaryngology, the First Affiliated Hospital, Sun Yat-Sen University and Institute of Otorhinolaryngology, Sun Yat-sen University, Guangzhou, 510080, People's Republic of China.|Department of Otorhinolaryngology, the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510260, People's Republic of China.
authors.forename: Ling
authors.initials: L
authors.lastname: Zong
authors.affiliation: Department of Otorhinolaryngology, the First Affiliated Hospital, Sun Yat-Sen University and Institute of Otorhinolaryngology, Sun Yat-sen University, Guangzhou, 510080, People's Republic of China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Otorhinolaryngology, the First Affiliated Hospital, Sun Yat-Sen University and Institute of Otorhinolaryngology, Sun Yat-sen University, Guangzhou, 510080, People's Republic of China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhan
authors.affiliation: Department of Otorhinolaryngology, the First Affiliated Hospital, Sun Yat-Sen University and Institute of Otorhinolaryngology, Sun Yat-sen University, Guangzhou, 510080, People's Republic of China.
authors.forename: Chang
authors.initials: C
authors.lastname: Dong
authors.affiliation: Department of Otorhinolaryngology, the First Affiliated Hospital, Sun Yat-Sen University and Institute of Otorhinolaryngology, Sun Yat-sen University, Guangzhou, 510080, People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: Cao
authors.affiliation: Department of Otorhinolaryngology, the First Affiliated Hospital, Sun Yat-Sen University and Institute of Otorhinolaryngology, Sun Yat-sen University, Guangzhou, 510080, People's Republic of China.
authors.forename: Haocheng
authors.initials: H
authors.lastname: Tang
authors.affiliation: Department of Otorhinolaryngology, the First Affiliated Hospital, Sun Yat-Sen University and Institute of Otorhinolaryngology, Sun Yat-sen University, Guangzhou, 510080, People's Republic of China. jhongy@mail.sysu.edu.cn.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Jiang
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D004252:DNA Mutational Analysis / Q000379:methods; D003638:Deafness / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D050259:Genes, Mitochondrial; D020022:Genetic Predisposition to Disease; D003639:Hearing Loss, Sudden / Q000235:genetics*; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000235:genetics*; D009154:Mutation; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012335:RNA, Ribosomal
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D012335:RNA, Ribosomal; C075526:RNA, ribosomal, 12S; D000072259:Connexin 26
keywords: GJB2; Mitochondrial 12S rRNA; Mutation; Sudden deafness; c.109G>A