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Application of a new molecular technique for the genetic evaluation of products of conception


  • Funding sources: KaryoLite™ BoBs™ reagents for this study were supplied by PerkinElmer, Wallac, Turku, Finland.

  • Conflicts of interest: Francesca R. Grati, Livia Marcato, Simona De Toffol, Francesca Malvestiti, Anna Maria Ruggeri, Federico Maggi and Giuseppe Simoni are full-time employees of the TOMA Advanced Biomedical Assays S.p.A. and declare no conflict of interest. Denise Molina Gomes, Laurence Loeuillet, Robert Wainer, Eleonore Blondeel and François Vialard are employees of the Hospital CHI Poissy St Germain and declare no conflict of interest. Devika Ganesamoorthy and Howard R. Slater are employees of the Royal Children's Hospital and declare no conflict of interest. Azzedine Aboura, Celine Dupont, Anne Claude Tabet and Fabien Guimiot are employees of the Hôpital Robert Debré and declare no conflict of interest.

Francesca R. Grati. E-mail:



Karyotyping is a well-established method of investigating the genetic content of product of conceptions (POCs). Because of the high rate of culture failure and maternal cell contamination, failed results or 46,XX findings are often obtained. Different molecular approaches that are not culture dependent have been proposed to circumvent these limits. On the basis of the robust experience previously obtained with bacterial artificial chromosomes (BACs)-on-Beads™ (BoBs™), we evaluated the same technology that we had used for the analysis of prenatal samples on POCs.


KaryoLite™ BoBs™ includes 91 beads, each of which is conjugated with a composite of multiple neighboring BACs according to the hg19 assembly. It quantifies proximal and terminal regions of each chromosome arm. The study included 376 samples.


The failure rate was 2%, and reproducibility >99%; false-positive and false-negative rates were <1% for non-mosaic aneuploidies and imbalances effecting all three BACs in a contig. Detection rate for partial terminal imbalances was 65.5%. The mosaic detection threshold was 50%, and the success rate in macerated samples was 87.8%. The aneuploidy detection rate in samples with cell growth failure was 27.8%, and maternal cell contamination was suspected in 23.1% of 46,XX cultured cells.


KaryoLite™ BoBs™ as a ‘first-tier’ test in combination with other approaches showed beneficial, cost-effective and clearly enhanced POC testing. © 2012 John Wiley & Sons, Ltd.