title: A novel frameshift mutation (c.405delC) in the GJB2 gene associated with autosomal recessive hearing loss in two Tunisian families.
abstract: OBJECTIVE
  Mutations in GJB2 are found to be responsible for 50% of congenital autosomal recessive non-syndromic hearing loss, one of the most important mutations in this gene is the c.35delG, which is responsible for the majority of GJB2 related deafness in the Tunisian population. The aim of this study was to determine the molecular etiology of hearing loss in two Tunisian individuals.
  
  
  METHODS
  We screened two Tunisian individuals affected by congenital, bilateral, profound, sensorineural hearing loss for mutations in GJB2 gene using PCR and direct sequencing.
  
  
  RESULTS
  We identified a novel frameshift mutation in the GJB2 gene, the c.405delC resulting in a truncated protein (p.Tyr136Thrfs*32). It was found in compound heterozygosity with the c.35delG in two non-consanguineous unrelated families from Tunisia. One patient underwent a cochlear implant at 4 years. Initial evaluations post-implantation indicate a successful cochlear implant outcome since the patient began to acquire language abilities and auditory sensation.
  
  
  CONCLUSIONS
  With this novel GJB2 mutation, the mutational spectrum of this gene continues to broaden in our population. The occurrence of biallelic GJB2 mutations for the other deaf girl, despite the neonatal pain and hypotension due to complicated delivery, led us to confirm the importance of GJB2 screening for cochlear implant candidates regardless of the etiology of deafness in populations with a relatively high frequency of GJB2 mutation carriers.
authors.affiliation: Laboratoire de Génomique Biomédicale et Oncogénétique, Institut Pasteur de Tunis, BP 74, 13 Place Pasteur, Tunis 1002, Tunisia.
authors.forename: Zied
authors.initials: Z
authors.lastname: Riahi
authors.forename: Houda
authors.initials: H
authors.lastname: Chahed
authors.forename: Habib
authors.initials: H
authors.lastname: Jaafoura
authors.forename: Rim
authors.initials: R
authors.lastname: Zainine
authors.forename: Olfa
authors.initials: O
authors.lastname: Messaoud
authors.forename: Mohamed
authors.initials: M
authors.lastname: Naili
authors.forename: Majdi
authors.initials: M
authors.lastname: Nagara
authors.forename: Hassan
authors.initials: H
authors.lastname: Hammami
authors.forename: Nadia
authors.initials: N
authors.lastname: Laroussi
authors.forename: Yosra
authors.initials: Y
authors.lastname: Bouyacoub
authors.forename: Rym
authors.initials: R
authors.lastname: Kefi
authors.forename: Crystel
authors.initials: C
authors.lastname: Bonnet
authors.forename: Ghazi
authors.initials: G
authors.lastname: Besbes
authors.forename: Sonia
authors.initials: S
authors.lastname: Abdelhak
mesh_terms: D000328:Adult; D002675:Child, Preschool; D019929:Cochlear Implantation / Q000379:methods*; D003054:Cochlear Implants; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D004252:DNA Mutational Analysis; D003638:Deafness / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics* / Q000601:surgery; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D005500:Follow-Up Studies; D016368:Frameshift Mutation / Q000235:genetics*; D005808:Genes, Recessive; D005820:Genetic Testing / Q000379:methods; D005838:Genotype; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics* / Q000601:surgery; D006579:Heterozygote; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010375:Pedigree; D016133:Polymerase Chain Reaction / Q000379:methods; D018570:Risk Assessment; D012494:Sampling Studies; D016896:Treatment Outcome; D014416:Tunisia
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26
keywords: Cochlear implant; GJB2; Hearing loss; Mutation; Novel; Tunisia