title: Prevalence and diagnostic spectrum of generalized retinal dystrophy in Danish children.
abstract: OBJECTIVE
  The aim of the present population-based cross-sectional study was to examine the prevalence and diagnostic spectrum of generalized retinal dystrophy in Danish children.
  
  
  METHODS
  The Danish Registry for the Blind and Partially Sighted Children comprises all visually impaired children residing in Denmark aged 0-17 years. Among registered children, the primary diagnosis of generalized retinal dystrophy was assessed by chart review, including fundus photographs and electroretinograms. Age-specific data for live children in Denmark were retrieved from Statistics Denmark.
  
  
  RESULTS
  Of the 1,204,235 Danish children aged 0-17 years on 1 October 2011, 2017 children were registered as visually impaired. Of these, 153 cases were attributed to generalized retinal dystrophy, corresponding to a prevalence of 13 per 100,000 children. The age-specific prevalence increased prominently with increasing age. In 43% of the children the eye condition was part of a syndrome, while the remaining 57% had eye disease only. The most common hereditary pattern was autosomal recessive (99 children, 66%).
  
  
  CONCLUSIONS
  This epidemiological survey demonstrates that the prevalence of generalized retinal dystrophy in Danish children is 13 per 100,000, which is a considerable increase compared to the 9.8 per 100,000 reported by Rosenberg in 1988. The prevalence of Leber congenital amaurosis, Usher syndrome, and Bardet-Biedl syndrome doubled, which may be explained by a documented history of consanguinity in more than one third of the children. Many of the dystrophies are the subject of clinical intervention trials, and nation-wide epidemiological data can help assess the future need for treatment.
authors.affiliation: National Eye Clinic for the Visually Impaired, Kennedy Center, Glostrup, Denmark. mettebertelsen12@gmail.com
authors.forename: Mette
authors.initials: M
authors.lastname: Bertelsen
authors.forename: Hanne
authors.initials: H
authors.lastname: Jensen
authors.forename: Michael
authors.initials: M
authors.lastname: Larsen
authors.forename: Birgit
authors.initials: B
authors.lastname: Lorenz
authors.forename: Markus N
authors.initials: MN
authors.lastname: Preising
authors.forename: Thomas
authors.initials: T
authors.lastname: Rosenberg
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D004596:Electroretinography; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015995:Prevalence; D012042:Registries; D058499:Retinal Dystrophies / Q000175:diagnosis / Q000453:epidemiology*; D014786:Vision Disorders / Q000175:diagnosis / Q000453:epidemiology