title: An evaluation of the role of environmental factors in the disease penetrance of cervical dystonia.
abstract: BACKGROUND
  Adult onset primary torsion dystonia (AOPTD) is a poorly penetrant autosomal dominant disorder; most gene carriers are non-manifesting despite having reached an adequate age for penetrance. It is hypothesised that genetic, epigenetic and environmental factors may exert protective or deleterious effects on penetrance of AOPTD. By examining environmental exposure history in cervical dystonia patients and their similarly aged unaffected siblings we aimed to determine the role of previous environmental exposures in relation to disease penetrance.
  
  
  METHODS
  A case-control study of 67 patients with cervical dystonia and 67 of their age-matched unaffected siblings was performed. Past environmental exposures were assessed using a detailed 124-question standardised questionnaire.
  
  
  RESULTS
  By univariate analysis, cervical dystonia patients, compared to their unaffected siblings, had an increased frequency of a history of car accidents with hospital attendance (OR 10.1, 95% CI 2.1 to 47.4, p=0.004) and surgical episodes (OR 6.5, 95% CI 1.76 to 23.61, p=0.005). Following multivariate analysis, car accidents with hospital attendance (OR 7.3, 95% CI 1.4 to 37.6, p=0.017) and all surgical episodes (OR 4.9, 95% CI 1.24 to 19.31, p=0.023) remained significantly associated with case status.
  
  
  CONCLUSIONS
  Cervical dystonia patients had a history, prior to symptom onset, of significantly more frequent episodes of surgery and of car accidents with hospital attendance than their age-matched unaffected siblings. Soft tissue trauma appears to increase risk of development of cervical dystonia in genetically predetermined individuals.
authors: Dept of Neurology, St. Vincent's University Hospital, Dublin, Ireland School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland.
authors: Anna
authors: A
authors: Molloy
authors: Dept of Neurology, St. Vincent's University Hospital, Dublin, Ireland School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland.
authors: Okka
authors: O
authors: Kimmich
authors: Dept of Neurology, St. Vincent's University Hospital, Dublin, Ireland School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland.
authors: Laura
authors: L
authors: Williams
authors: Trinity Centre for Bioengineering, Trinity College Dublin, Dublin, Ireland.
authors: John S
authors: JS
authors: Butler
authors: Dept of Neurology, St. Vincent's University Hospital, Dublin, Ireland School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland.
authors: Niall
authors: N
authors: Byrne
authors: Department of Neurophysiology, Beaumont Hospital, Dublin, Ireland.
authors: Fiona
authors: F
authors: Molloy
authors: Department of Neurology, Cork University Hospital, Cork, Ireland.
authors: Helena
authors: H
authors: Moore
authors: Department of Neurology, Beaumont Hospital, Dublin, Ireland.
authors: Daniel G
authors: DG
authors: Healy
authors: Dublin Neurological Institute, Mater Misericordiae Hospital, Dublin, Ireland.
authors: Tim
authors: T
authors: Lynch
authors: Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK.
authors: Mark J
authors: MJ
authors: Edwards
authors: Department of Statistics, Trinity College Dublin, Dublin, Ireland.
authors: Cathal
authors: C
authors: Walsh
authors: Trinity Centre for Bioengineering, Trinity College Dublin, Dublin, Ireland.
authors: Richard B
authors: RB
authors: Reilly
authors: Dept of Neurology, St. Vincent's University Hospital, Dublin, Ireland School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland.
authors: Sean
authors: S
authors: O'Riordan
authors: Dept of Neurology, St. Vincent's University Hospital, Dublin, Ireland School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland.
authors: Michael
authors: M
authors: Hutchinson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002869:Chromosome Aberrations; D004421:Dystonia / Q000151:congenital; D005260:Female; D059647:Gene-Environment Interaction; D006580:Genetic Carrier Screening; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D019683:Penetrance; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014103:Torticollis / Q000151:congenital* / Q000235:genetics
keywords: DYSTONIA; EPIDEMIOLOGY; GENETICS