title: Sibling concordance for clinical features of Duchenne and Becker muscular dystrophies.
abstract: BACKGROUND
  The correlation of markers of disease severity among brothers with Duchenne or Becker muscular dystrophy has implications for clinical guidance and clinical trials.
  
  
  METHODS
  Sibling pairs with Duchenne or Becker muscular dystrophy (n = 60) were compared for ages when they reached clinical milestones of disease progression, including ceased ambulation, scoliosis of ≥ 20°, and development of cardiomyopathy.
  
  
  RESULTS
  The median age at which younger brothers reached each milestone, compared with their older brothers ranged from 25 months younger for development of cardiomyopathy to 2 months older for ceased ambulation. For each additional month of ambulation by the older brother, the hazard of ceased ambulation by the younger brother decreased by 4%.
  
  
  CONCLUSIONS
  The ages when siblings reach clinical milestones of disease vary widely between siblings. However, the time to ceased ambulation for older brothers predicts the time to ceased ambulation for their younger brothers.
authors.affiliation: College of Public Health, University of Arizona, Tucson, Arizona, USA.
authors.forename: Sydney
authors.initials: S
authors.lastname: Pettygrove
authors.forename: Zhenqiang
authors.initials: Z
authors.lastname: Lu
authors.forename: Jennifer G
authors.initials: JG
authors.lastname: Andrews
authors.forename: F John
authors.initials: FJ
authors.lastname: Meaney
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Sheehan
authors.forename: Elinora T
authors.initials: ET
authors.lastname: Price
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Fox
authors.forename: Shree
authors.initials: S
authors.lastname: Pandya
authors.forename: Lijing
authors.initials: L
authors.lastname: Ouyang
authors.forename: Susan D
authors.initials: SD
authors.lastname: Apkon
authors.forename: Zoe
authors.initials: Z
authors.lastname: Powis
authors.forename: Christopher
authors.initials: C
authors.lastname: Cunniff
mesh_terms: D000367:Age Factors; D009202:Cardiomyopathies / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D006801:Humans; D015994:Incidence; D008297:Male; D020388:Muscular Dystrophy, Duchenne / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D011379:Prognosis; D012189:Retrospective Studies; D012600:Scoliosis / Q000453:epidemiology; D035781:Siblings
keywords: Becker muscular dystrophy; Duchenne muscular dystrophy; ambulation; cardiomyopathy; scoliosis; sibling features
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