title: Nonsyndromic 35 delG mutation of the connexin 26 gene associated with deafness in syndromic children: two case reports.
abstract: OBJECTIVE
  Several genetic diseases, such as velocardiofacial syndrome Del(22q11) and Down syndrome, are associated with hearing impairment.
  
  
  METHODS
  Case reports.
  
  
  METHODS
  The authors reported two cases of hearing-impaired children, one with Del (22q11) and one with Down syndrome, both with bilateral nonevolutive profound sensorineural deafness. Because of unusual features of their deafness and familial history, genetic evaluation was proposed. A homozygous 35delG mutation on the Connexin 26 gene was found in both children (DFNB1 phenotype).
  
  
  RESULTS
  A review of the reported otological features of Del (22q11) and Down syndrome showed that sensorineural deafness is rare and seldom profound. The authors found no evidence for a genetic link between Del(22q11) or Down syndrome and 35delG mutation on the Connexin 26 gene.
  
  
  CONCLUSIONS
  The case reports reveal a coincidental association between DFNB1 and a multiple congenital anomaly syndrome. The clinician must be aware of this type of association to manage genetic counseling, appropriate otological care, and suitable treatment.
authors.affiliation: Service ENT Department, University Hospital Montpellier, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Venail
authors.forename: Anne-Françoise
authors.initials: AF
authors.lastname: Roux
authors.forename: Nathalie
authors.initials: N
authors.lastname: Pallares-Ruiz
authors.forename: Mireille
authors.initials: M
authors.lastname: Claustres
authors.forename: Patricia
authors.initials: P
authors.lastname: Blanchet
authors.forename: Quentin
authors.initials: Q
authors.lastname: Gardiner
authors.forename: Michel
authors.initials: M
authors.lastname: Mondain
mesh_terms: D002648:Child; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics*; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D019465:Craniofacial Abnormalities / Q000235:genetics*; D004314:Down Syndrome / Q000235:genetics*; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation; D010641:Phenotype; D013577:Syndrome
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26