title: Synaptic defects at meiosis I and non-obstructive azoospermia.
abstract: BACKGROUND
  Recent advances in immunofluorescence methodology have made it possible to directly monitor protein localization patterns in germ cells undergoing meiosis. We used this technology to examine the early stages of meiosis in testicular material obtained from men presenting for evaluation at infertility clinics.
  
  
  METHODS
  Specifically, we compared meiotic progression, synapsis and recombination in 34 individuals with obstructive azoospermia ('controls') to 26 individuals with non-obstructive azoospermia (NOA) ('cases').
  
  
  RESULTS
  In 9 of the 26 cases, no germ cells were identified, but in the remaining 17, there was at least some progression through meiosis. Most of these individuals appeared to have normal levels of spermatogenic activity, with little evidence of meiotic impairment. However, in three individuals, we observed either complete or partial meiotic arrest associated with abnormalities in synapsis.
  
  
  CONCLUSIONS
  This suggests that >10% of cases of unexplained NOA may be attributable to severe meiotic defects. The characterization of these meiotic arrest phenotypes may guide further research into the molecular basis of unexplained infertility.
authors.affiliation: School of Molecular Biosciences, Washington State University, Pullman, WA, USA. dtopping@wsu.edu
authors.forename: Daniel
authors.initials: D
authors.lastname: Topping
authors.forename: Petrice
authors.initials: P
authors.lastname: Brown
authors.forename: LuAnn
authors.initials: L
authors.lastname: Judis
authors.forename: Stuart
authors.initials: S
authors.lastname: Schwartz
authors.forename: Allen
authors.initials: A
authors.lastname: Seftel
authors.forename: Anthony
authors.initials: A
authors.lastname: Thomas
authors.forename: Terry
authors.initials: T
authors.lastname: Hassold
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D053713:Azoospermia / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D023902:Chromosome Pairing; D041322:Chromosomes, Human, Y; D020022:Genetic Predisposition to Disease; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008540:Meiosis; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D009845:Oligospermia / Q000235:genetics; D011995:Recombination, Genetic; D013091:Spermatogenesis
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D000070957:MutL Protein Homolog 1