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Rare diseases in disabled children: an epidemiological survey
  1. P Guillem1,
  2. C Cans2,
  3. E Robert-Gnansia3,
  4. S Aymé4,
  5. P S Jouk5
  1. 1
    Register for Disabled Children and the Isère county Perinatal Survey, Grenoble, France
  2. 2
    Department of Medical Information and Data Processing, Grenoble University Hospital, France
  3. 3
    Register for Congenital Malformations from Centre and East of France, Lyon, France
  4. 4
    INSERM/Orphanet, Paris, France
  5. 5
    Department of Genetics and Procreation, Grenoble University Hospital, France
  1. Professor P S Jouk, Département de Génétique et Procréation, Centre Hospitalier Universitaire, BP 217, 38 043 Grenoble Cedex 09, France; PSJouk{at}


Aim: To estimate the contribution of rare diseases (RD) to severe impairment in 7-year-old children.

Methods: Data from a morbidity register of childhood impairments in a single French region were used. Impairments were classified as a mental, sensorial, neuromuscular (skeletal or movement-related) impairment (MSN_I) according to the International Classification of Functioning. Details of children born from 1980 to 1994 and resident in the county under study when they were 7 years old were recorded. A rare disease was defined as a prevalence rate of <1 per 2000 general population.

Results: 26% of children with severe MSN_I had a rare disease; in 36% the MSN_I was of unknown origin. The proportion of impairments that were due to a rare disease varied according to the type of impairment: 3.3% for severe psychiatric disorders; 16.0% for intellectual impairment; 37.2% for hearing impairment; 41.2% for neuromuscular, skeletal and movement impairment; and 81.1% for visual impairment. The overall prevalence rate of rare diseases was 2.1 per 1000 (459/218 283), and it increased significantly over time (p = 0.003). The latter increase was not associated with a decrease in the proportion of impairments of unknown origin, indicating an improvement in the survival of the children with a rare disease.

Conclusions: In this study, a rare disease was at the origin of 26% of cases of severe MSN_I. This proportion remained stable over time, whereas the prevalence rate, as well as the prevalence rate of MSN_I disability, increased over time.

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  • Competing interests: None.