Page 116 - ESHRE2019

Embryo mosaicism: Fact or Artifact?
Opponents of mosaicism claim that false positives may arise as a consequence of artifacts (i.e. inclusion of a whole chromosome) introduced by WGA (Capalbo et al., Hum Reprod, 2017)
However, if a CCS method is properly validated (with cell lines mixture models), it is unlikely that the shift of the dots determined from hypothetical WGA artifacts can be misinterpreted as mosaicism occurrences.
Validation studies have been performed for array-CGH (Mamas et al., 2012; Novik et al. 2014; Greco et al., 2015), and more recently for NGS (Maxwell et al., Fertil Steril 2016; Vera-Rodríguez et al., Fertil Steril 2016; Fragouli et al., 2017; Spinella et al., 2018), all demonstrating that these CCS methods are able to reliably detect mosaicism.
Step1: Workflow of single-cell isolation and reconstitution experiments
Cell culture
46,XY, 45,XY +21
Single-cell isolation
FACSAria
Cell sorter
mixing different ratios of single cells (euploid and with known chromosomal aneuploidies)
Spinella et al. 2017 Fertil Steril 2018;109:77-83
Cell mix
10 cells
Cell lysis
100 cells 1000 cells
WGA NGS
%Mosaicism
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Total
No. of samples
116
18
18
18
18
18
18
18
18
18
17
295
114
111