Multi-center Study to Validate niPGT-A

Summary

Participation Requirements

Description

Human embryos have higher aneuploidy rates (20-80%) than other species. A considerable proportion of these aneuploid embryos have the ability to reach the blastocyst stage. However, depending on the aneuploidy type, some will fail to implant in the uterus, while others will implant but will be unabl...

Human embryos have higher aneuploidy rates (20-80%) than other species. A considerable proportion of these aneuploid embryos have the ability to reach the blastocyst stage. However, depending on the aneuploidy type, some will fail to implant in the uterus, while others will implant but will be unable to carry out early embryonic development (miscarriage), or very rarely, result in liveborn children with specific abnormalities. It is therefore important to identify aneuploid embryos It is important to identify embryos at risk for aneuploid chromosomes in patients with advanced maternal age (AMA), recurrent implantation failure (RIF) or recurrent miscarriage (RM). The identification of aneuploidies is especially important in embryos from patients with higher aneuploidy risk such as those with advanced maternal age (AMA), recurrent implantation failure (RIF), or recurrent miscarriage (RM). Therefore, normal embryo morphology and development are dependent on the chromosomal complement. PGT-A technique analyse the full chromosome content of a single cell with high sensitivity and specificity but requires an invasive biopsy to obtain embryonic material for the genetic analysis. Thus, non-invasive methods to replace the existing invasive testing method would be useful in the improvement of maternal and fetal safety. Recently, there have been many research advances in the field of genetic testing. Cell-free DNA (cfDNA) has been observed in spent embryo culture media. The origin of the cfDNA at the blastocyst stage could be attributed to apoptotic events which may occur during normal development. This has encouraged different research groups to carry out analysis spent culture media. Various studies were initially carried out to detect specific genes associated with monogenic disorders (MTHFR9, HBA1/HBA210, SRY11). Recently, non-invasive PGT-A has been developed, with highly variable results on the concordance rate (3.5%,59.1%, and 85.7%, 30.6%). The chromosomal status of the embryo from the DNA present in the spent culture medium was compared to the one obtained following the standard protocol using trophectoderm biopsy. The difference in the reported results can be related to the different methodologies applied because different amplification and detection methods -aCGH or NGS- were used. Moreover, the concordance rates were defined differently on each study, i.e. aneuploid results in spent culture media and trophectoderm biopsy could be considered concordant despite of showing not the same aneuploid chromosomes. The impact of culture conditions in the efficiency of the non-invasive approach has been investigated by Hammond et al, (2016). They found that there was consistently a very low level of DNA contamination (mitochondrial and nuclear DNA) in media controls, from three different types of commercial media, that had not been exposed to embryos. The low baseline level of DNA contamination observed is thought to originate from the protein supplement of the culture media. Finally, there could be influence of two relevant factors on PGT-A: contamination with maternal DNA from granulosa cells (MCC) and mosaicism. To improve the results of IVF (In vitro Fertilization) programs, there is a need to identify the embryo with highest implantation potential. Embryo chromosomal analysis allows the selection of euploid embryos, which have a higher implantation success rate. The development of a non-invasive PGT-A protocol will improve the current methodologies used to identify those euploid embryos avoiding the detrimental effect of the biopsy on the embryo and decreasing the economic cost. The initial estimated sample size calculated was 3245 embryos (each embryo is considered as a subject in the study), considering a dropout rate of 30%. Data will be grouped and analyzed at Igenomix at three time points of the study: once 25 embryos of each center have been processed (to assess the implementation of the methodology), after the 30% of the samples have been processed (as an interim to check the results) and at the end of the study for the final analysis including the follow up of the clinical outcome. After the interim analysis performed at 30% of recruitment, the total sample size has been recalculated as 2620 samples, considering a drop-out rate of 5% according to the drop-out rate observed during the interim analysis. Results of the interim analysis published in Rubio et al., AJOG 2020.

Tracking Information