title: Epidemiological, clinical and genetic aspects of adult onset isolated focal dystonia in Ireland.
abstract: Adult onset idiopathic isolated focal dystonia presents with a number of phenotypes. Reported prevalence rates vary considerably; well-characterized cohorts are important to our understanding of this disorder.
  
  
  
  To perform a nationwide epidemiological study of adult onset idiopathic isolated focal dystonia in the Republic of Ireland.
  
  
  
  Patients with adult onset idiopathic isolated focal dystonia were recruited from multiple sources. Diagnosis was based on assessment by a neurologist with an expertise in movement disorders. When consent was obtained, a number of clinical features including family history were assessed.
  
  
  
  On the prevalence date there were 592 individuals in Ireland with adult onset idiopathic isolated focal dystonia, a point prevalence of 17.8 per 100 000 (95% confidence interval 16.4-19.2). Phenotype numbers were cervical dystonia 410 (69.2%), blepharospasm 102 (17.2%), focal hand dystonia 39 (6.6%), spasmodic dysphonia 18 (3.0%), musician's dystonia 17 (2.9%) and oromandibular dystonia six (1.0%). Sixty-two (16.5%) of 375 consenting index cases had a relative with clinically confirmed adult onset idiopathic isolated focal dystonia (18 multiplex and 24 duplex families). Marked variations in the proportions of patients with tremor, segmental spread, sensory tricks, pain and psychiatric symptoms by phenotype were documented.
  
  
  
  The prevalence of adult onset idiopathic isolated focal dystonia in Ireland is higher than that recorded in many similar service-based epidemiological studies but is still likely to be an underestimate. The low proportion of individuals with blepharospasm may reflect reduced environmental exposure to sunlight in Ireland. This study will serve as a resource for international comparative studies of environmental and genetic factors in the pathogenesis of the disorder.
authors.affiliation: Department of Neurology, St Vincent's University Hospital, Dublin, Ireland.|School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland.
authors.forename: L
authors.initials: L
authors.lastname: Williams
authors.affiliation: Department of Neurology, St Vincent's University Hospital, Dublin, Ireland.|School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland.
authors.forename: E
authors.initials: E
authors.lastname: McGovern
authors.affiliation: Department of Neurology, St Vincent's University Hospital, Dublin, Ireland.|School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland.
authors.forename: O
authors.initials: O
authors.lastname: Kimmich
authors.affiliation: Department of Neurology, St Vincent's University Hospital, Dublin, Ireland.|School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland.
authors.forename: A
authors.initials: A
authors.lastname: Molloy
authors.affiliation: Department of Neurology, St Vincent's University Hospital, Dublin, Ireland.|School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland.
authors.forename: I
authors.initials: I
authors.lastname: Beiser
authors.affiliation: Trinity Centre for Bioengineering, Dublin and School of Mathematical Sciences, Dublin Institute of Technology, Dublin, Ireland.
authors.forename: J S
authors.initials: JS
authors.lastname: Butler
authors.affiliation: Beaumont Hospital, Dublin, Ireland.
authors.forename: F
authors.initials: F
authors.lastname: Molloy
authors.affiliation: Beaumont Hospital, Dublin, Ireland.
authors.forename: P
authors.initials: P
authors.lastname: Logan
authors.affiliation: Beaumont Hospital, Dublin, Ireland.
authors.forename: D G
authors.initials: DG
authors.lastname: Healy
authors.affiliation: Mater Misericordiae University Hospital, Dublin, Ireland.
authors.forename: T
authors.initials: T
authors.lastname: Lynch
authors.affiliation: Adelaide and Meath Hospital, Dublin, Ireland.
authors.forename: R
authors.initials: R
authors.lastname: Walsh
authors.affiliation: Royal Victoria Eye and Ear Hospital, Dublin, Ireland.
authors.forename: L
authors.initials: L
authors.lastname: Cassidy
authors.affiliation: Royal Victoria Eye and Ear Hospital, Dublin, Ireland.
authors.forename: P
authors.initials: P
authors.lastname: Moriarty
authors.affiliation: Cork University Hospital, Cork, Ireland.
authors.forename: H
authors.initials: H
authors.lastname: Moore
authors.affiliation: Cork University Hospital, Cork, Ireland.
authors.forename: T
authors.initials: T
authors.lastname: McSwiney
authors.affiliation: Departments of Statistics, Trinity College Dublin, University of Limerick, Limerick, Ireland.
authors.forename: C
authors.initials: C
authors.lastname: Walsh
authors.affiliation: Department of Neurology, St Vincent's University Hospital, Dublin, Ireland.|School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland.
authors.forename: S
authors.initials: S
authors.lastname: O'Riordan
authors.affiliation: Department of Neurology, St Vincent's University Hospital, Dublin, Ireland.|School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland.
authors.forename: M
authors.initials: M
authors.lastname: Hutchinson
mesh_terms: D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D001764:Blepharospasm / Q000453:epidemiology / Q000209:etiology; D018450:Disease Progression; D020821:Dystonic Disorders / Q000150:complications / Q000453:epidemiology* / Q000235:genetics*; D004777:Environment; D005260:Female; D006801:Humans; D007494:Ireland / Q000453:epidemiology; D008297:Male; D001523:Mental Disorders / Q000209:etiology / Q000523:psychology; D008875:Middle Aged; D015995:Prevalence; D012737:Sex Factors; D013472:Sunlight; D014202:Tremor / Q000209:etiology / Q000503:physiopathology; D055815:Young Adult
keywords: adult onset idiopathic isolated focal dystonia; epidemiology; genetics; prevalence; primary dystonia; sex ratios