title: Sperm chromosome analysis of an infertile patient with a 95% mosaic r(21) karyotype and normal phenotype.
abstract: OBJECTIVE
  To examine sperm meiotic segregation in a man with mosaic ring chromosome 21.
  
  
  METHODS
  Case report.
  
  
  METHODS
  Hospital departments of reproductive biology, cytogenetics, gynecology, and obstetrics.
  
  
  METHODS
  One patient referred for cryptozoospermia, heterozygous for a ring chromosome.
  
  
  METHODS
  Fluorescence in situ hybridization with chromosome 21-specific probes after sperm selection.
  
  
  RESULTS
  A total of 169 spermatozoa were selected; 92.3% carried a normal 21 chromosome, 6.5% the ring chromosome, and 1.2% both.
  
  
  CONCLUSIONS
  Ring chromosome frequency in mature sperm cells was low and may be due to preferential meiosis of normal spermatogonia,which could explain the cryptozoospermia and unexpected ratio in this case.
authors.affiliation: Department of Reproductive Biology, Centre Hospitalier Intercommunal de Poissy, Poissy, France.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Hammoud
authors.forename: Denise Molina
authors.initials: DM
authors.lastname: Gomes
authors.forename: Marianne
authors.initials: M
authors.lastname: Bergere
authors.forename: Robert
authors.initials: R
authors.lastname: Wainer
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Selva
authors.forename: François
authors.initials: F
authors.lastname: Vialard
mesh_terms: D020090:Chromosome Segregation; D002891:Chromosomes, Human, Pair 21; D004314:Down Syndrome / Q000235:genetics; D005838:Genotype; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007248:Infertility, Male / Q000235:genetics* / Q000503:physiopathology; D007621:Karyotyping; D008297:Male; D008540:Meiosis / Q000235:genetics; D009030:Mosaicism; D010641:Phenotype; D027724:Reproductive Techniques, Assisted; D012303:Ring Chromosomes; D018570:Risk Assessment; D055101:Semen Analysis; D013076:Sperm Count; D013081:Sperm Motility; D013091:Spermatogenesis / Q000235:genetics*