title: Effectiveness of prenatal chromosomal analysis using multicolor fluorescent in situ hybridisation.
abstract: OBJECTIVE
  To evaluate the clinical effectiveness of multicolour fluorescent in situ hybridisation (FISH) analysis in routine prenatal diagnosis.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  3,203 amniotic fluid samples.
  
  
  METHODS
  Unique DNA (chromosomes 13 and 21) and alpha satellite centromeric-specific (chromosomes X, Y and 18) probes were used in two mixes to permit the simultaneous analysis of several chromosomes. The performance of multicolour FISH and conventional cytogenetic analysis was compared.
  
  
  RESULTS
  Conventional cytogenetic analysis identified 111 chromosomal abnormalities, of which 94 were potentially detectable by the FISH technique and 97 would be typically associated with neonatal phenotypic abnormalities. Multicolour FISH analysis detected 84% (93/111) of all chromosome abnormalities and 99% (93/94) of abnormalities where there was a specific probe. The sensitivity of multicolour FISH analysis was 95% (92/97) for chromosomal abnormalities likely to result in an abnormal postnatal outcome. Multiple ultrasound abnormalities were detected in all five cases of clinically relevant chromosomal abnormalities missed by multicolour FISH. FISH results were available within 48 hours and the sample failure rate was 0 x 1% (3/3,202).
  
  
  CONCLUSIONS
  Multicolour FISH analysis is a sensitive and reliable technique for the rapid prenatal diagnosis of chromosomal abnormalities. Examining only five chromosomes allowed 95% of clinically relevant chromosomal abnormalities to be diagnosed correctly. As routine antenatal screening is targeted at the major autosomal trisomies and sex chromosome aneuploidies, multicolour FISH analysis may potentially replace conventional cytogenetic analysis in routine prenatal diagnosis.
authors.affiliation: St George's Hospital Medical School, Academic Department of Obstetrics and Gynaecology, London, UK.
authors.forename: B
authors.initials: B
authors.lastname: Thilaganathan
authors.forename: S
authors.initials: S
authors.lastname: Sairam
authors.forename: T
authors.initials: T
authors.lastname: Ballard
authors.forename: C
authors.initials: C
authors.lastname: Peterson
authors.forename: R
authors.initials: R
authors.lastname: Meredith
mesh_terms: D002869:Chromosome Aberrations / Q000175:diagnosis*; D025063:Chromosome Disorders; D003116:Color; D005260:Female; D005820:Genetic Testing / Q000379:methods; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008297:Male; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D011446:Prospective Studies; D012680:Sensitivity and Specificity