Non-invasive human preimplantation embryos sex determination using STR-based fluorescent multiplex PCR on days 3 and 5 post-fertilization.

Abstract

This study aimed to investigate the efficacy of cell-free DNA (CF-DNA) in the spent cleavage and blastocyst medium versus blastomere biopsy for sex identification using short tandem repeat (STR) markers for the first time. In total, 39 samples of spent culture medium (SCM) from six couples were collected of which 28 samples were CF-DNA from blastocoel fluid + SCM (day 5) and 11 samples from SCM alone (day 3). The frequencies of allele dropout (ADO), fail rate and informativity markers were considered. The relationship between the morphology of embryos and ADO and the fail number of all markers was investigated. Sex identification rate between CF-DNA isolated from culture medium and fluorescence in situ hybridization (FISH) was then compared with measurement of Agreement Kappa (AK). The highest frequency of informative markers belonged to DXS6801 and HPRT. There was no relationship between the ADO number of all markers and embryo morphology. A significant difference was seen between embryo morphology and fail numbers. AK value between CF-DNA isolated from culture medium and FISH was 0.516, which is moderate. The ability of CF-DNA to detect the correct diagnosis of males and females showed that all values of specificity, sensitivity, positive predictive value, and negative predictive value were 100%. The presence of embryonic CF-DNA in the SCM on day 3 as well as blastocyst medium on day 5 using STR-based multiplex PCR is approximately consistent with FISH for sex identification. Advances in DNA extraction, amplification technique, and testing may allow for preimplantation genetic testing for aneuploidy (PGT-A) and monogenic/single-gene disorders (PGT-M) as a non-invasive approach without biopsy in the future either in sex determination or chromosomal abnormality.