title: GJB2 and GJB6 screening in Tunisian patients with autosomal recessive deafness.
abstract: Autosomal recessive nonsyndromic deafness (ARNSD or DFNB) is a very common genetically heterogenous disorder. Although DFNB1 mutations are known to be the most frequent cause of this disorder, they are largely dependent on ethnic groups. The aims of our study are to specify the prevalence and the spectrum of GJB2 mutations as well as the prevalence of GJB6 large deletion in Tunisian population.
  
  
  METHODS
  95 unrelated patients with moderate to severe sensorineural hearing loss have been tested. The GJB2 coding region has been studied by PCR/Sequencing and the del(GJB6-D13S1830) mutation has been screened by fluorescent PCR multiplex.
  
  
  RESULTS
  27.36% of patients present mutations on both alleles of GJB2 gene and no one has the del(GJB6-D13S1830) mutation. The c.35delG mutation represents 86.5% of GJB2 deafness alleles and is found in homozygous state in 22 patients and in heterozygous state in one patient. Four other mutations are detected in four probands: two are compound heterozygous for the p.V37I/p.E47X and the c.35delG/p.R184P mutations, and two are homozygous for the p.E47X and the c.333-334delAA mutations.
  
  
  CONCLUSIONS
  Our results showed that c.35delG is the most common but not the only GJB2 mutation and that the del(GJB6-del D13S1830) is absent in our cohort. Consequently, we propose a systematic sequencing of GJB2 coding region for ARNSD Tunisian patients and we suggest additional studies to specify the real prevalence of del(GJB6-D13S1830) in our population.
authors: Charles Nicolle Hospital, Congenital and Hereditary Diseases, Tunis, Tunisia. mediha_tr@yahoo.fr
authors: Mediha
authors: M
authors: Trabelsi
authors: Wafa
authors: W
authors: Bahri
authors: Marwene
authors: M
authors: Habibi
authors: Rim
authors: R
authors: Zainine
authors: Faouzi
authors: F
authors: Maazoul
authors: Besbes
authors: B
authors: Ghazi
authors: Habiba
authors: H
authors: Chaabouni
authors: Ridha
authors: R
authors: Mrad
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D000072259:Connexin 26; D000075302:Connexin 30; D017630:Connexins / Q000235:genetics*; D003638:Deafness / Q000235:genetics; D005260:Female; D005808:Genes, Recessive; D005820:Genetic Testing; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006801:Humans; D008297:Male; D008403:Mass Screening; D009154:Mutation; D016133:Polymerase Chain Reaction; D015995:Prevalence; D017422:Sequence Analysis, DNA; D014416:Tunisia; D055815:Young Adult
chemical_list: D000075302:Connexin 30; D017630:Connexins; C000607042:GJB2 protein, human; C491020:GJB6 protein, human; D000072259:Connexin 26