title: A study of GJB2 and delGJB6-D13S1830 mutations in Brazilian non-syndromic deaf children from the Amazon region.
abstract: Hearing impairment affects about 1 in 1000 newborns. Mutations in the connexin 26 (GJB2) gene rank among the most frequent causes of non-syndromic deafness in different populations, while delGJB6-D13S1830 mutation located in the DFNB30 locus is known to cause sensorineural hearing loss. Despite the many studies on the involvement of GJB2 mutations in hearing impairment in different populations, there is little information on genetic deafness in Brazil, especially in the Amazon region.
  
  
  OBJECTIVE
  To determine the prevalence of GJB2 mutations and delGJB6-D13S1830 in 77 sporadic non-syndromic deaf patients.
  
  
  METHODS
  The coding region of the GJB2 gene was sequenced and polymerase chain reaction was performed to detect the delGJB6-D13S1830 mutation.
  
  
  RESULTS
  Mutant allele 35delG was found in 9% of the patients (7/77). Mutations M34T and V95M were detected in two distinct heterozygous patients. Non-pathogenic mutation V27I was detected in 28.6% of the patients (22/77). None of the deaf patients carried the delGJB6-D13S1830 mutation.
  
  
  CONCLUSIONS
  Mutant alleles on gene GJB2 were observed in 40% (31/77) of the subjects in the sample. Pathogenic variants were detected in only 12% (9/77) of the individuals. More studies are required to elucidate the genetic causes of hearing loss in miscegenated populations.
authors.affiliation: Instituto Ciencias Biológicas, Universidade Federal do Pará, Brazil.
authors.forename: Luciana Santos Serrão de
authors.initials: LS
authors.lastname: Castro
authors.forename: Anderson Nonato do Rosario
authors.initials: AN
authors.lastname: Marinho
authors.forename: Elzemar Martins Ribeiro
authors.initials: EM
authors.lastname: Rodrigues
authors.forename: Giorgio Christie Tavares
authors.initials: GC
authors.lastname: Marques
authors.forename: Tarcísio André Amorim de
authors.initials: TA
authors.lastname: Carvalho
authors.forename: Luiz Carlos Santana da
authors.initials: LC
authors.lastname: Silva
authors.forename: Sidney Emanuel Batista
authors.initials: SE
authors.lastname: dos Santos
mesh_terms: D002648:Child; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006801:Humans; D009154:Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26