title: Prenatal detection by subtelomeric FISH and MLPA of unbalanced meiotic recombinants resulting from parental pericentric inversions.
abstract: OBJECTIVE
  Pericentric inversion carriers are predisposed to produce unbalanced gametes that result in conceptuses having either a partial trisomy for one distal segment and a partial monosomy for the other or vice versa. Larger inversions result in smaller unbalanced distal segments and a higher likelihood of a viable fetus. In these cases the structure of the recombinant chromosome is similar to the original balanced inverted or normal ones despite the (unbalanced) genetic content. Such cases may not be detected prenatally by conventional cytogenetic analysis.
  
  
  METHODS
  In all prenatal samples from the pericentric inversion carriers we applied subtelomeric FISH probes specific for the chromosome involved in order to detect parental meiotic recombinants resulting from a single cross-over event. Confirmatory MLPA was also applied in unbalanced fetuses.
  
  
  RESULTS
  The occurrence of a duplication deficiency unbalance from pericentric inversion carriers was successfully detected in all three fetuses by FISH. MLPA assays applied in two cases confirmed these results.
  
  
  CONCLUSIONS
  The application of commercial FISH subtelomeric probes is a reliable method that could be routinely applied for the detection of single cross-over meiotic recombinants. MLPA is a sound alternative technique.
authors.affiliation: Research and Development, Cytogenetics and Molecular Biology, TOMA Advanced Biomedical Assays S.p.A., Via Ferrer 25/27, 21052 Busto Arsizio, Varese, Italy. fgrati@tomalab.com
authors.forename: Francesca R
authors.initials: FR
authors.lastname: Grati
authors.forename: Sara
authors.initials: S
authors.lastname: Chinetti
authors.forename: Roberta
authors.initials: R
authors.lastname: Malgara
authors.forename: Giulia
authors.initials: G
authors.lastname: Rognoni
authors.forename: Beatrice
authors.initials: B
authors.lastname: Grimi
authors.forename: Simona
authors.initials: S
authors.lastname: De Toffol
authors.forename: Silvia
authors.initials: S
authors.lastname: Milani
authors.forename: Francesca
authors.initials: F
authors.lastname: Dulcetti
authors.forename: Giuditta
authors.initials: G
authors.lastname: Frascoli
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Di Meco
authors.forename: Rosaria
authors.initials: R
authors.lastname: Liuti
authors.forename: Anna
authors.initials: A
authors.lastname: Trotta
authors.forename: Jordy
authors.initials: J
authors.lastname: Coffa
authors.forename: Federico
authors.initials: F
authors.lastname: Maggi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Simoni
mesh_terms: D007446:Chromosome Inversion; D020732:Cytogenetic Analysis / Q000379:methods; D005260:Female; D005333:Fetus / Q000502:physiology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D007621:Karyotyping; D008297:Male; D008540:Meiosis / Q000235:genetics*; D011296:Prenatal Diagnosis / Q000379:methods*; D011995:Recombination, Genetic; D016615:Telomere / Q000235:genetics