title: Abnormal progression through meiosis in men with nonobstructive azoospermia.
abstract: OBJECTIVE
  To study meiotic abnormalities in men with nonobstructive azoospermia.
  
  
  METHODS
  Analysis of synaptonemal complex and recombination in testicular tissue.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Twenty-nine men with nonobstructive azoospermia and 12 men with normal spermatogenesis.
  
  
  METHODS
  Testicular tissues were processed with immunofluorescent staining using antibodies against proteins associated with synaptonemal complex and recombination events.
  
  
  METHODS
  Synaptonemal complex configuration and recombination in meiosis I.
  
  
  RESULTS
  In patients with nonobstructive azoospermia, a marked heterogeneity in spermatogenesis was found: nearly half of them had a complete absence of meiotic cells, one case had germ cells arrested at the zygotene stage of meiotic prophase, and, in general, the rest had impaired fidelity of chromosome synapsis and recombination in pachytene cells. Compared with controls, these patients had significantly more cells in leptotene/zygotene and higher frequencies of unpaired chromosome regions in pachytene. Significantly reduced recombination, an increased frequency of achiasmate autosome bivalents, and sex univalents in pachytene were also observed in these patients with nonobstructive azoospermia.
  
  
  CONCLUSIONS
  Defects in chromosome synapsis and decreased recombination during meiotic prophase may have led to spermatogenesis arrest and contributed in part to the unexplained infertility in these patients.
authors.affiliation: Department of Medical Genetics, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Fei
authors.initials: F
authors.lastname: Sun
authors.forename: Paul
authors.initials: P
authors.lastname: Turek
authors.forename: Calvin
authors.initials: C
authors.lastname: Greene
authors.forename: Evelyn
authors.initials: E
authors.lastname: Ko
authors.forename: Alfred
authors.initials: A
authors.lastname: Rademaker
authors.forename: Renée H
authors.initials: RH
authors.lastname: Martin
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D053713:Azoospermia / Q000503:physiopathology*; D002352:Carrier Proteins / Q000032:analysis; D005455:Fluorescent Antibody Technique; D006801:Humans; D008297:Male; D008540:Meiosis / Q000502:physiology*; D000070957:MutL Protein Homolog 1; D009687:Nuclear Proteins / Q000032:analysis; D011995:Recombination, Genetic; D013573:Synaptonemal Complex / Q000502:physiology; D013737:Testis / Q000166:cytology* / Q000503:physiopathology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D000070957:MutL Protein Homolog 1