European Child & Adolescent Psychiatry

, Volume 23, Issue 1, pp 35–43

A Danish population-based twin study on autism spectrum disorders


    • Department of Child and Adolescent Psychiatry OdenseUniversity of Southern Denmark
  • Meta Jørgensen
    • Psychiatric Hospital for Children and AdolescentsAarhus University Hospital
  • Kirsten Ohm Kyvik
    • Institute of Regional Health Services Research and Odense Patient Data Explorative Network (OPEN)University of Southern Denmark
  • Niels Bilenberg
    • Department of Child and Adolescent Psychiatry OdenseUniversity of Southern Denmark
Original Contribution

DOI: 10.1007/s00787-013-0419-5

Cite this article as:
Nordenbæk, C., Jørgensen, M., Kyvik, K.O. et al. Eur Child Adolesc Psychiatry (2014) 23: 35. doi:10.1007/s00787-013-0419-5


Genetic epidemiological studies of Autism Spectrum Disorders (ASDs) based on twin pairs ascertained from the population and thoroughly assessed to obtain a high degree of diagnostic validity are few. All twin pairs aged 3–14 years in the nationwide Danish Twin Registry were approached. A three-step procedure was used. Five items from the “Child Behaviour Checklist” (CBCL) were used in the first screening phase, while screening in the second phase included the “Social and Communication Questionnaire” and the “Autism Spectrum Screening Questionnaire”. The final clinical assessment was based on “gold standard” diagnostic research procedures including diagnostic interview, observation and cognitive examination. Classification was based on DSM-IV-TR criteria. The initial sample included 7,296 same-sexed twin pairs and, after two phases of screening and clinical assessment, the final calculations were based on 36 pairs. The probandwise concordance rate for ASD was 95.2 % in monozygotic (MZ) twins (n = 13 pairs) and 4.3 % in dizygotic (DZ) twins (n = 23 pairs). The high MZ and low DZ concordance rate support a genetic aetiology to ASDs.


Autism spectrum disordersTwinsConcordance ratesPopulation basedScreening

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© Springer-Verlag Berlin Heidelberg 2013