title: Jervell and Lange-Nielsen syndrome in Norwegian children: aspects around cochlear implantation, hearing, and balance.
abstract: OBJECTIVE
  Jervell and Lange-Nielsen syndrome (JLNS) is a rare cause of autosomal recessive inherited deafness. JLNS patients are candidates for cochlear implantation, and represent a group that needs special attention and precautions. The aim of this article is to draw some guidelines for dealing with these patients, and to emphasize the importance of electrocardiography (ECG) screening of congenitally deaf patients. A probable vestibular dysfunction is also discussed.
  
  
  METHODS
  Eight of 273 implanted children (2.9%) at Rikshospitalet-Radiumhospitalet Medical Center, Oslo, Norway have been diagnosed with JLNS. All the children were evaluated with ECG, six of them before cochlear implantation. Auditory perception was evaluated with the littlEARS Auditory Questionnaire, or with a test battery developed at Rikshospitalet-Radiumhospitalet Medical Center. DNA sequencing was used to screen for mutations in the genes KCNQ1 and KCNE1. The cases are presented and discussed in a retrospective case review.
  
  
  RESULTS
  Two of the children are dead. The corrected QT (QTc) interval in the ECG was markedly prolonged in all the children (median QTc, 0.59 sec; range, 0.53-0.65). Six children have more than 1 yr experience with their cochlear implant. Four of them are performing average or above compared with the other implanted children. All the children have mutations in the KCNQ1 gene. Six of our patients have delayed gross motor development, and the remaining two are markedly delayed compared with their older siblings.
  
  
  CONCLUSIONS
  Cochlear implantation can be performed safely and with good results in children with JLNS, but requires knowledge of the diagnosis and necessary precautions have to be taken. ECG should be taken for all children with congenital deafness, preferably before exposure to strong sound stimuli. Vestibular dysfunction seems to be a part of JLNS, but this needs further investigation.
authors.affiliation: Department of Otolaryngology, Faculty Division Rikshospitalet, University of Oslo, Norway. geir.siem@rikshospitalet.no
authors.forename: Geir
authors.initials: G
authors.lastname: Siem
authors.forename: Andreas
authors.initials: A
authors.lastname: Früh
authors.forename: Trond P
authors.initials: TP
authors.lastname: Leren
authors.forename: Ketil
authors.initials: K
authors.lastname: Heimdal
authors.forename: Erik
authors.initials: E
authors.lastname: Teig
authors.forename: Sten
authors.initials: S
authors.lastname: Harris
mesh_terms: D002648:Child; D002675:Child, Preschool; D019929:Cochlear Implantation / Q000706:statistics & numerical data*; D004562:Electrocardiography; D005260:Female; D015870:Gene Expression / Q000235:genetics; D006311:Hearing Disorders / Q000175:diagnosis / Q000235:genetics / Q000601:surgery; D006801:Humans; D007223:Infant; D029593:Jervell-Lange Nielsen Syndrome / Q000453:epidemiology / Q000235:genetics / Q000601:surgery; D051657:KCNQ1 Potassium Channel / Q000235:genetics; D008297:Male; D009664:Norway / Q000453:epidemiology; D004856:Postural Balance; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics; D012189:Retrospective Studies
chemical_list: C489622:KCNE1 protein, human; D051657:KCNQ1 Potassium Channel; C496909:KCNQ1 protein, human; D024642:Potassium Channels, Voltage-Gated