title: Meiotic chromosome abnormalities in fertile men: are they increasing?
abstract: OBJECTIVE
  To determine the basal frequencies of meiotic chromosome abnormalities in fertile men.
  
  
  METHODS
  Descriptive design.
  
  
  METHODS
  Research university laboratory and clinical andrology service.
  
  
  METHODS
  Seventeen fertile donors undergoing vasectomy.
  
  
  METHODS
  Analysis of testicular biopsies.
  
  
  METHODS
  Meiotic chromosome abnormalities in metaphase I spermatocytes.
  
  
  RESULTS
  A total of 1,407 spermatocytes I was analyzed. The main meiotic abnormality was absence or low chiasma number of individual bivalents (23.4%), followed by structural (3.3%) and numerical (0.7%) abnormalities. Sex chromosomes and G-group chromosomes were the most commonly found as univalents at metaphase I. Statistically significant heterogeneity was found for meiotic abnormalities among fertile men, caused by interindividual variation in the level of dissociated sex chromosomes (ranging from 3.2% to 43.7%). The mean total percentage of meiotic abnormalities in spermatocytes I from fertile men was 27.4%, 1.7 times higher than those described a few decades ago in fertile and even in infertile men.
  
  
  CONCLUSIONS
  Fertile men are a heterogeneous group for meiotic errors, with individuals showing percentages of meiotic abnormalities as high as 50%. From these findings, caution is recommended when using meiotic studies to diagnose and provide genetic counselling to patients consulting for infertility.
authors.affiliation: Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain.
authors.forename: Laia
authors.initials: L
authors.lastname: Uroz
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Rajmil
authors.forename: Cristina
authors.initials: C
authors.lastname: Templado
mesh_terms: D000328:Adult; D002869:Chromosome Aberrations / Q000706:statistics & numerical data*; D005298:Fertility / Q000502:physiology*; D006801:Humans; D007248:Infertility, Male / Q000453:epidemiology* / Q000235:genetics; D008297:Male; D008540:Meiosis / Q000502:physiology*; D008875:Middle Aged; D013094:Spermatozoa / Q000502:physiology; D014659:Vasectomy / Q000706:statistics & numerical data