Article Text

De novo apparently balanced translocations in man are predominantly paternal in origin and associated with a significant increase in paternal age
  1. N Simon Thomas1,2,
  2. Joan K Morris3,
  3. Julia Baptista1,2,4,
  4. Bee Ling Ng5,
  5. John A Crolla1,2,
  6. Patricia A Jacobs1,2
  1. 1Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury, UK
  2. 2Division of Human Genetics, University of Southampton, Southampton, UK
  3. 3Centre for Environmental and Preventive Medicine, Wolfson Institute of Preventive Medicine, Charterhouse Square, London, UK
  4. 4Medical Genetics Unit, Department of Gynecology, Obstetrics and Pediatrics, University of Bologna, Bologna, Italy
  5. 5The Wellcome Trust Sanger Institute, The Genome Research Campus, Hinxton, Cambridgeshire, UK
  1. Correspondence to Dr N Simon Thomas, Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury SP2 8TE, UK; simon.thomas{at}


Background Congenital chromosome abnormalities are relatively common in our species and among structural abnormalities the most common class is balanced reciprocal translocations. Determining the parental origin of de novo balanced translocations may provide insights into how and when they arise. While there is a general paternal bias in the origin of non-recurrent unbalanced rearrangements, there are few data on parental origin of non-recurrent balanced rearrangements.

Methods The parental origin of a series of de novo balanced reciprocal translocations was determined using DNA from flow sorted derivative chromosomes and linkage analysis.

Results Of 27 translocations, we found 26 to be of paternal origin and only one of maternal origin. We also found the paternally derived translocations to be associated with a significantly increased paternal age (p<0.008).

Conclusion Our results suggest there is a very pronounced paternal bias in the origin of all non-recurrent reciprocal translocations and that they may arise during one of the numerous mitotic divisions that occur in the spermatogonial germ cells prior to meiosis.

  • genetics
  • clinical genetics
  • cytogenetics
  • molecular genetics

Statistics from


  • Funding Other funders: Wellcome Trust.

  • Competing interests None.

  • Ethics approval This study was conducted with the approval of the Salisbury/Southampton.

  • Patient consent Not required.

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

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