title: Suspected gonadal mosaicism for isochromosomes 18p and 18q unsubstantiated by fluorescence in situ hybridization analysis of sperm.
abstract: OBJECTIVE
  A father had two children, one with isochromosome 18p, and another with isochromosome 18q. The father was counseled that he might have gonadal mosaicism for isochromosomes 18p and 18q, which could confer a high recurrence risk.
  
  
  METHODS
  A sperm sample from the father was analyzed with fluorescence in situ hybridization probes for 18p and 18q.
  
  
  RESULTS
  More than 1,000 sperm were scored and none were found with two 18p or 18q signals. There were no differences in the father's specimen compared to a control.
  
  
  CONCLUSIONS
  There was no evidence for gonadal mosaicism. It is important to confirm clinical hypotheses whenever possible.
authors.affiliation: Department of Pediatrics, Gundersen Lutheran Medical Center, La Crosse, Wisconsin 54601, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Williams
authors.forename: K D
authors.initials: KD
authors.lastname: Josephson
authors.forename: N
authors.initials: N
authors.lastname: Gursoy
authors.forename: C
authors.initials: C
authors.lastname: Jackson-Cook
mesh_terms: D002887:Chromosomes, Human, Pair 18 / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D018404:Isochromosomes / Q000235:genetics*; D008297:Male; D008423:Maternal Age; D009030:Mosaicism / Q000235:genetics*; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D013094:Spermatozoa / Q000378:metabolism*