Accuracy of direct mutation testing by TaqMan quantitative polymerase chain reaction for preimplantation genetic diagnosis of recurrent de novo mutations.

OBJECTIVE

To assess the accuracy and allele dropout (ADO) rate of preimplantation genetic testing for monogenic disease (PGT-M) when performing direct mutation testing alone, in the absence of family member-based linkage analysis.

DESIGN

Retrospective evaluation of concordance between direct mutation testing using TaqMan quantitative polymerase chain reaction (qPCR) and linkage-based analysis to estimate ADO rates when linkage is unavailable.

SUBJECTS: In vitro fertilization (IVF) patients who had their embryos evaluated for PGT-M.

EXPOSURE: None.

MAIN OUTCOME MEASURES: Mendelian ratio and accuracy of TaqMan qPCR.

RESULTS

A total of 189 cases underwent both linkage analysis and direct mutation testing, involving 262 IVF cycles and 1,226 embryos, resulting in the generation of 1,719 genotypes from trophectoderm samples. Among these, 51 genotypes (3.0%) were from embryos with aneuploidies affecting the chromosome carrying the mutation of interest. The observed genotypic distribution of embryos generally aligned with expected Mendelian ratios. Concordance between linkage analysis and direct testing was high at 99.2% (1,705 of 1,719 genotypes). Notably, seven discordant genotypes were attributed to ADO in point mutations, with an additional seven discordances observed in cases involving insertions or deletions.

CONCLUSION

Analysis of direct mutation genotyping of trophectoderm biopsies revealed an accuracy of 99.2%.