J Med Genet doi:10.1136/jmedgenet-2011-100147
  • Short report

De novo copy number variants associated with intellectual disability have a paternal origin and age bias

Press Release
  1. Joris A Veltman1
  1. 1Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences and Institute for Genetic and Metabolic Disorders, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
  2. 2Unitat de Genètica, Universitat Pompeu Fabra, and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona, Spain
  3. 3Department of Cognitive Neuroscience, Donders Institute for Brain Cognition and Behavior, Radboud University Nijmegen, The Netherlands
  1. Correspondence to Dr Jayne Y Hehir-Kwa, Department of Human Genetics-848, Radboud University Nijmegen Medical Centre, PO Box 9101, Nijmegen, The Netherlands; j.hehir{at}
  1. Contributors JHK and BRS contributed equally to this work. JHK developed the algorithms used in this study. JHK, BRS, and LV performed the analysis, revised and drafted the manuscript. JKB collected and provided the control cohort. RP and NL analysed the microarray data, and LPJ and JV initiated the collaboration that led to this study and contributed to the manuscript.

  • Received 26 April 2011
  • Revised 27 July 2011
  • Accepted 6 August 2011
  • Published Online First 3 October 2011


Background De novo mutations and structural rearrangements are a common cause of intellectual disability (ID) and other disorders with reduced or null reproductive fitness. Insight into the genomic and environmental factors predisposing to the generation of these de novo events is therefore of significant clinical importance.

Methods This study used information from single nucleotide polymorphism microarrays to determine the parent-of-origin of 118 rare de novo copy number variations (CNVs) detected in a cohort of 3443 patients with ID.

Results The large majority of these CNVs (76%, p=1.14×10−8) originated on the paternal allele. This paternal bias was independent of CNV length and CNV type. Interestingly, the paternal bias was less pronounced for CNVs flanked by segmental duplications (64%), suggesting that molecular mechanisms involved in the formation of rare de novo CNVs may be dependent on the parent-of-origin. In addition, a significantly increased paternal age was only observed for those CNVs which were not flanked by segmental duplications (p=0.02).

Conclusion This indicates that rare de novo CNVs are increasingly being generated with advanced paternal age by replication based mechanisms during spermatogenesis.


  • JY H-K and B R-S shared first authorship on this paper.

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.

Free sample
This recent issue is free to all users to allow everyone the opportunity to see the full scope and typical content of JMG.
View free sample issue >>

Don't forget to sign up for content alerts so you keep up to date with all the articles as they are published.

Navigate This Article