title: De novo apparently balanced translocations in man are predominantly paternal in origin and associated with a significant increase in paternal age.
abstract: 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury SP2 8TE, UK. simon.thomas@salisbury.nhs.uk
authors.forename: N Simon
authors.initials: NS
authors.lastname: Thomas
authors.forename: Joan K
authors.initials: JK
authors.lastname: Morris
authors.forename: Julia
authors.initials: J
authors.lastname: Baptista
authors.forename: Bee Ling
authors.initials: BL
authors.lastname: Ng
authors.forename: John A
authors.initials: JA
authors.lastname: Crolla
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Jacobs
mesh_terms: D000328:Adult; D056905:Chromosome Breakpoints; D005260:Female; D008040:Genetic Linkage; D006801:Humans; D008297:Male; D008875:Middle Aged; D010331:Paternal Age; D010641:Phenotype; D017422:Sequence Analysis, DNA / Q000379:methods*; D014178:Translocation, Genetic