title: Meiotic and sperm aneuploidy studies in three carriers of Robertsonian translocations and small supernumerary marker chromosomes.
abstract: OBJECTIVE
  To study the meiotic behaviour of one carrier of a small supernumerary marker chromosome (sSMC): 47,XY,+mar; one carrier of a Robertsonian translocation (ROB): 45,XY,rob(13;21) (q10;q10); and one carrier of both a sSMC and a ROB: 46,XY,rob(13;21) (q11.1;q11.1),+mar.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  University-affiliated research center and hospital.
  
  
  METHODS
  Subfertile men with ROB and sSMC.
  
  
  METHODS
  None.
  
  
  METHODS
  The chromosomal origin of the sSMC was assessed by multiplex fluorescence in situ hybridization. The segregation of the ROB and sSMC in sperm and possible interchromosomal effects were examined by fluorescence in situ hybridization. Synapsis, meiotic recombination, and meiotic inactivation were investigated in ejaculate spermatocytes of the 47,XY,+mar and 45,XY,rob(13;21) carriers using immunostaining.
  
  
  RESULTS
  In the 47,XY,+mar and 46,XY,rob(13;21),+mar carriers, the sSMC was found in 13.5% and 11.5 % of sperm, respectively. Analysis of meiotic segregation of chromosome 13 and 21 showed that 91.2% of sperm were normal/balanced in the 46,XY,rob(13;21),+mar case, whereas 88.4% of sperm were normal/balanced in the 45,XY,rob(13;21) case. Interchromosomal effects involving the sex chromosomes were found in both sSMC carriers. Both 47,XY,+mar and 45,XY,rob(13;21) carriers showed decreased global recombination, impaired synapsis, and an association of abnormal chromosomes with the XY body.
  
  
  CONCLUSIONS
  Carriers of marker chromosomes produce sperm with markers at frequencies lower than theoretically expected. Carriers of ROB and sSMC showed decreased recombination, impaired synapsis, and association of abnormal chromosomes with the XY body, which may contribute to an interchromosomal effect. Using immunofluorescence techniques to analyze ejaculate-derived spermatocytes from subfertile men provides a novel technique for examining meiosis without the need for a testicular biopsy.
authors: Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada.
authors: Gordon
authors: G
authors: Kirkpatrick
authors: Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada.
authors: He
authors: H
authors: Ren
authors: Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany.
authors: Thomas
authors: T
authors: Liehr
authors: Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada.
authors: Victor
authors: V
authors: Chow
authors: Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address: sai@mail.ubc.ca.
authors: Sai
authors: S
authors: Ma
mesh_terms: D000782:Aneuploidy; D016022:Case-Control Studies; D002869:Chromosome Aberrations; D023902:Chromosome Pairing; D002877:Chromosomes, Human; D002882:Chromosomes, Human, Pair 13; D002891:Chromosomes, Human, Pair 21; D041321:Chromosomes, Human, X; D041322:Chromosomes, Human, Y; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008540:Meiosis / Q000235:genetics*; D049471:Pachytene Stage / Q000235:genetics; D010641:Phenotype; D013094:Spermatozoa / Q000378:metabolism / Q000473:pathology*; D014178:Translocation, Genetic
keywords: Meiotic recombination; Robertsonian translocation; interchromosomal effects; sex body association; small supernumerary marker chromosomes