Parameters of poor prognosis in preimplantation genetic testing for monogenic disorders

Aneuploidy rates and likelihood of obtaining a usable embryo for transfer among in vitro fertilization cycles using preimplantation genetic testing for monogenic disorders and aneuploidy compared with in vitro fertilization cycles using preimplantation genetic testing for aneuploidy alone

OBJECTIVE

To compare aneuploidy rates among in vitro fertilization (IVF) cycles using preimplantation genetic testing for monogenic disorders (PGT-M) and aneuploidy (PGT-A) compared with IVF cycles using PGT-A alone, and to determine the likelihood of obtaining at least one usable embryo in cycles using PGT-M+PGT-A compared with cycles using PGT-A alone.

DESIGN

Retrospective cohort study.

SETTING

Single genetics laboratory.

PATIENT(S)

All IVF cycles for patients aged 18-45 undergoing PGT-A with or without concurrent PGT-M at a single genetics laboratory from November 2019 to March 2023.

INTERVENTION(S)

Use of PGT-M+PGT-A vs. use of PGT-A alone.

MAIN OUTCOME MEASURE(S)

Per cycle aneuploidy rate stratified by age, and per cycle likelihood of obtaining at least one usable embryo stratified by age and inheritance pattern of monogenic disease.

RESULT(S)

A total of 72,522 IVF cycles were included; 4,255 cycles (5.9%) using PGT-M+PGT-A and 68,267 cycles (94.1%) using PGT-A alone. The PGT-M+PGT-A group was younger than the PGT-A alone group (<35 years old: 56.1% vs. 30.5%). The majority of PGT-M cycles were performed for autosomal dominant pathogenic variants (42.4%), followed by autosomal recessive (36.5%), X-linked dominant (13.3%), and X-linked recessive (7.5%). The median number of embryos biopsied was higher in PGT-A alone compared with PGT-M+PGT-A cycles for patients aged <35, but it was equivalent in all other age groups. Age stratified aneuploidy rates did not significantly differ between PGT-M+PGT-A compared with PGT-A alone cycles. The probability of having a usable embryo declined with increasing age across all inheritance patterns. Compared with PGT-A alone, PGT-M+PGT-A cycles for patients aged ≤40 across all inheritance patterns were significantly less likely to yield a usable embryo, except in cycles for autosomal recessive diseases in the 38-40 age group and X-linked recessive diseases in the 35-37 age group. There were no consistent differences seen between groups in patients over 40. Cycles for patients with autosomal dominant diseases had the lowest likelihood of yielding a usable embryo for patients aged <43.

CONCLUSION(S)

In vitro fertilization cycles using PGT-M+PGT-A have similar age-specific aneuploidy rates to those using PGT-A alone. Cycles for patients ≤40 using PGT-M+PGT-A are significantly less likely to yield a usable embryo compared with those using PGT-A alone.

A heatmap for expected cumulative live birth rate in preimplantation genetic testing for monogenic disorders and chromosomal structural rearrangements

PURPOSE

Our objective is to predict the cumulative live birth rate (CLBR) and identify the specific subset within the population undergoing preimplantation genetic testing for monogenic disorders (PGT-M) and chromosomal structural rearrangements (PGT-SR) which is likely to exhibit a diminished expected CLBR based on various patient demographics.

METHODS

We performed a single-centre retrospective cohort study including 1522 women undergoing 3130 PGT cycles at a referral centre for PGT. A logistic regression analysis was performed to predict the CLBR per ovarian stimulation in women undergoing PGT-M by polymerase chain reaction (PCR) or single-nucleotide polymorphism (SNP) array, and in women undergoing PGT-SR by SNP array, array comparative genomic hybridization (CGH) or next-generation sequencing (NGS).

RESULTS

The mean age of women was 32.6 years, with a mean AMH of 2.75 µg/L. Female age and AMH significantly affected the expected CLBR irrespective of the inheritance mode or PGT technology. An expected CLBR < 10% was reached above the age of 42 years and AMH ≤ 1.25 µg/L. We found no significant difference in outcome per ovarian stimulation between the different PGT technologies, i.e. PCR, SNP array, array CGH and NGS. Whereas per embryo transfer, we noticed a significantly higher probability of live birth when SNP array, array CGH and NGS were used as compared to PCR.

CONCLUSION

In a PGT-setting, couples with an unfavourable female age and AMH should be informed of the prognosis to allow other reproductive choices. The heatmap produced in this study can be used as a visual tool for PGT couples.

A clinical predictive model for live birth in women of advanced age undergoing PGT cycles

PURPOSE

The trend of delaying childbirth has resulted in a growing number of advanced-aged women who are opting for preimplantation genetic testing (PGT) to screen for monogenic diseases or structural chromosomal rearrangements (PGT-M and PGT-SR). This increase in demand necessitates the development of a clinical predictive model for live birth outcomes in these women. Therefore, the objective of this study is to construct a comprehensive predictive model that assesses the likelihood of achieving a successful live birth in advanced-aged women undergoing PGT-M and PGT-SR treatments.

METHODS

A retrospective cohort study of 37-45-year-old women undergoing preimplantation genetic testing for monogenic disease or structural chromosomal rearrangement cycles from 2010 to 2021 was conducted at a university hospital reproductive centre. The purpose was to develop a clinical predictive model for live birth in these women. The main outcome studied was the cumulative live birth rate in the first or subsequent cycles. Developing a decision tree enabled a comprehensive study of clinical parameters and expected outcomes.

RESULTS

The analysis included 158 women undergoing 753 preimplantation genetic testing cycles. The cumulative live birth rate was 37.342% (59/158). Decision tree analysis revealed that women aged ≤ 40.1 or women > 40.1 with one or more top-quality transferable embryos in their first cycle had the best chance for a live baby (56% and 41%, respectively). Those older than 40.1 without top-quality embryos and seven or fewer dominant follicles had no live births. A Kaplan-Meier curve showed that for autosomal dominant diseases, there was a negligible increase in live birth rate after three cycles, compared to six cycles in autosomal recessive inheritance.

CONCLUSION

In older women, the chance of delivering after repeated cycles is higher in those with at least one top-quality unaffected embryo in their first preimplantation genetic testing cycle. Additional preimplantation genetic testing cycles after three in carriers of an autosomal dominant disorder and six in those with an autosomal recessive disorder should be considered prudently.

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.

Preimplantation genetic testing in patients with genetic susceptibility to cancer

Data on preimplantation genetic testing (PGT-M) in patients with genetic susceptibility to cancer are scarce in the literature, while there is, in our experience, a growing familiarity with assisted reproduction techniques (ART) among pathogenic variant heterozygotes. We performed a retrospective multicenter study of PGT-M outcomes among French patients with genetic susceptibility to cancer. Our objectives were to collect data on this complex issue, and to help cancer geneticists counsel their patients of reproductive age. We also wanted to increase awareness regarding PGT-M among cancer genetics professionals. Patients from three university hospital cancer genetics clinics who had requested PGT-M between 2000 and 2019 were included retrospectively. Data were extracted from medical records. Patients were then contacted directly to collect missing and up-to-date information. Out of 41 eligible patients, 28 agreed explicitly to participate when contacted and were therefore included. They carried PV in VHL (n = 9), APC (n = 8), CDH1 (n = 5), STK11 (n = 2), AXIN2, BRCA1, MEN1, and FH (n = 1). Seven patients were denied PGT-M based on multidisciplinary team meetings or subsequently by the ART hospital teams, two changed their minds, and two were yet to start the process. PGT-M was successful in seven patients (25%), with a mean age at PGT-M request of 27. Most had von Hippel-Lindau. PGT-M failed in the remaining ten, with a mean age at PGT-M request of 32. The main reason for failure was non-implantation of the embryo. Of these, four patients were pursuing PGT-M at the time of last contact. PGT-M outcomes in patients with cancer susceptibility syndromes were satisfactory. These patients should be informed about PGT-M more systematically, which would imply greater awareness among cancer genetics professionals regarding ART. Our series was not representative of cancer susceptibility syndromes in general; the predominance of cases with syndromes characterized by early-onset, highly penetrant disease is explained by the restrictive French guidelines.