Clinical guidelines for IVF with PGD for HLA matching

Chinese experts' consensus guideline on preimplantation genetic testing of monogenic disorders

Recent developments in molecular biological technologies and genetic diagnostic methods, accompanying with updates of relevant terminologies, have enabled the improvements of new strategies of preimplantation genetic testing for monogenic (single gene) disorders (PGT-M) to prevent the transmission of inherited diseases. However, there has been much in the way of published consensus on PGT-M. To properly regulate the application of PGT-M, Chinese experts in reproductive medicine and genetics have jointly developed this consensus statement. The consensus includes indications for patient selection, genetic and reproductive counseling, informed consent, diagnostic strategies, report generation, interpretation of results and patient follow-ups. This consensus statement serves to assist in establishment of evidence-based clinical and laboratory practices for PGT-M.

Genetic Counseling and Assisted Reproductive Technologies

Despite the ever-increasing number of patients undergoing fertility treatments and the expanded use of genetic testing in this context, there has been limited focus in the literature on the involvement of genetics professionals in the assisted reproductive technology (ART) setting. Here we discuss the importance of genetic counseling within reproductive medicine. We review how genetic testing of embryos is performed, the process of gamete donation, the challenges associated with genetic testing, and the complexities of genetic test result interpretation.

Role of aneuploidy screening in preimplantation genetic testing for monogenic diseases in young women

OBJECTIVE

To investigate whether aneuploidy screening in preimplantation genetic testing (PGT) for monogenic diseases improves the ongoing pregnancy/live birth rate of single frozen/thawed embryo transfer (FET) cycles in young women.

DESIGN

Retrospective cohort study.

SETTING

Single university-based fertility center.

PATIENT(S)

From January 2016 to December 2017, 569 FET cycles were selected for analysis. The aneuploidy screening (AS) group included 131 FET cycles from 105 oocyte retrieval cycles in 98 patients who underwent PGT for monogenic diseases with aneuploidy screening, and the non-AS group included 438 FET cycles from 280 oocyte retrieval cycles in 266 patients who underwent PGT for monogenic diseases without aneuploidy screening.

INTERVENTION(S)

The patient population was all under the age of 35 years and underwent PGT for monogenic diseases with and without AS.

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy/live birth rate, live birth rate, implantation rate, and miscarriage rate.

RESULT(S)

Aneuploidy screening significantly improved the ongoing pregnancy/live birth rate (61.22% vs. 43.98%), implantation rate (64.29% vs. 50.38%), and live birth rate (53.06% vs. 36.09%) of young women carrying monogenic diseases in the first FET cycles. When adjusted for the parity, number of previous miscarriages, and percentage of infertility, the likelihood of implantation was 1.874 times higher (95% confidence interval 1.126-3.119), and an ongoing pregnancy/live birth was 2.139 times more likely (95% confidence interval 1.295-3.534). In addition, the miscarriage rate was significantly decreased (3.17% vs. 11.94%). In the cumulative pregnancy outcomes, the cumulative ongoing pregnancy/live birth rate both per transfer and per patient were significantly higher in the AS group (62.24% vs. 50.38% and 79.59% vs. 68.80%), but no difference existed after adjusting for the parity, number of previous miscarriage, and percentage of infertility. Nevertheless, aneuploidy screening reduced the time interval from the first ET to the achievement a pregnancy.

CONCLUSION(S)

Aneuploidy screening in PGT significantly improved the ongoing pregnancy/live birth rate of young women carrying monogenic diseases in the first FET cycles.

Pre-implantation genetic diagnosis and pre-implantation genetic screening: two years experience at a single center

Objective

Indications for preimplantation genetic diagnosis (PGD)/preimplantation genetic screening (PGS) cycles and clinical outcomes were evaluated at CHA Gangnam Medical Center.

Methods

This is retrospective cohort study. All patients (n=336) who went through in vitro fertilization (IVF)-PGD/PGS cycles (n=486) between January 2014 and December 2015 were included in Fertility Center of CHA Gangnam Medical Center. Patients underwent IVF-PGD/PGS with 24-chromosome screening. Patients with euploid embryos had transfer of one or 2 embryos in a fresh cycle with any subsequent frozen embryo transfer (ET) cycle. Compared implantation, clinical pregnancy, ongoing pregnancy, and early abortion rates were the main outcome measures.

Results

The most common indication for PGD/PGS was recurrent spontaneous abortion (n=160). The chromosome rearrangement cases (n=116) included 24 Robertsonian translocations, 60 reciprocal translocations, 3 inversions, 2 deletions, 4 additions, and 23 mosaicisms. PGS cases rather than the PGD cases showed higher implantation rates (26.4% vs. 20.3%), ongoing pregnancy rates (19.5% vs. 16.4%), and clinical pregnancy rates (28.6% vs. 23.3%). Implantation rates (30.3% vs. 23.7%), clinical pregnancy rates (39.2% vs. 25.2%), and ongoing pregnancy rates (25.7% vs. 17.5%) were significant higher in the blastocyst evaluation group than cleavage stage evaluation group.

Conclusion

This was the largest study of PGD/PGS for 2 years at a single center in Korea. The pregnancy outcomes of PGD cases are slightly lower than PGS cases. It was confirmed again that success rate of PGD/PGS is higher if biopsy was done at blastocyst than cleavage stage.

Novel Multiplex Fluorescent PCR-Based Method for HLA Typing and Preimplantational Genetic Diagnosis of β-Thalassemia

BACKGROUND AND AIMS

Thalassemia is curable by bone marrow transplantation; however, finding suitable donors with defined HLA combination remains a major challenge. Cord blood stem cells with preselected HLA system through preimplantation genetic diagnosis (PGD) proved very useful for resolving scarce HLA-matched bone marrow donors.

METHODS

A thalassemia trait couple with an affected child was included in this study. We used informative STR markers at the HLA and beta globin loci to develop a single cell multiplex fluorescent PCR protocol. The protocol was extensively optimized on single lymphocytes isolated from the couple's peripheral blood. The optimized protocol was applied on single blastomeres biopsied from day 3 cleavage stage IVF embryos of the couple.

RESULTS

Four IVF embryos biopsied on day 3 and a single blastomere of each were provided for genetic diagnosis of combined β-thalassemia mutations and HLA typing. Of these, one embryo was diagnosed as homozygous normal for the thalassemia mutation and HLA matched with the existing affected sibling.

CONCLUSION

The optimized protocol worked well in PGD clinical cycle for selection of thalassemia-unaffected embryos with the desired HLA system.

Pre-implantation genetic diagnosis and screening: now and the future

Since 1989, the year of the first pre-implantation genetic diagnosis (PGD), many developments occurred both in assisted reproduction techniques and in molecular tools. While PGD is a well-established and documented application, pre-implantation genetic screening (PGS) for the detection of aneuploid embryos is still debated due to the presence of mosaicism in the embryo, but especially to the knowledge of the limits that label an embryo as healthy or as appropriate to the life. The aim of this review is to present the state-of-the-art in the field of PGD and PGS, illustrating its benefits and limitations, along with biopsy techniques and the use of new high-throughput technologies.