The influence of balanced complex chromosomal rearrangements on preimplantation embryonic development potential and molecular karyotype

BACKGROUND

Balanced complex chromosome rearrangements (BCCR) are balanced chromosomal structural aberrations that involve two or more chromosomes and at least three breakpoints. It is very rare in the population. The objective is to explore the difference of influence of three types of BCCR on early embryonic development and molecular karyotype.

RESULTS

Twelve couples were recruited including four couples of three-way rearrangements carriers (group A), three couples of double two-way translocations carriers (group B) and five couples of exceptional CCR carriers (group C). A total of 243 oocytes were retrievedin the seventeen preimplantation genetic testing (PGT) cycles, and 207 of these were available for fertilization. After intracytoplasmic sperm injection, 181oocytes normally fertilized. The rates of embryos forming on day3 in three groups were 87.88, 97.78 and77.14%, which was significantly different (P = 0.01). Compared with group B, the rate of embryo formation was statistically significantly lower in group C (P = 0.01). Furthermore, the rates of high-quality blastocysts in three group were 14.71, 48.15 and 62.96%, respectively, which was significantly different (P = 0.00). Compared with group B andC, the rate of high-quality blastocysts in group A was statistically significantly lower (P = 0.00;P = 0.00). Comprehensive chromosome analysis was performed on 83 embryos, including 75 trophectodermcellsand 8 blastomeres. Except 7 embryos failed to amplify, 9.01%embryos were diagnosed as euploidy, and 90.91% were diagnosed as abnormal. As for group A, the euploid embryo rate was 10.71%and the abnormal embryo rate was 89.29%. In group B,the euploid embryo rate was 3.85%, the abnormal embryo rate was 96.15%. The euploid embryo rate was 13.04%, the abnormal embryo rate was 86.96% in group C. There were no significant differences among the three groups (P = 0.55).

CONCLUSIONS

The lowest rate of high quality blastocysts has been for three-way rearrangements and the lowest rate of euploidy has been for double two-way translocations, although no significant difference. Different types of BCCR maybe have little effect on the embryonic molecular karyotype. The difference of influence of BCCR on early embryonic developmentandmolecular karyotypeshould be further studied.

The fertility willingness and acceptability of preimplantation genetic testing in Chinese patients with autosomal dominant polycystic kidney disease

Background

With the development and progression of genetic technology, preimplantation genetic testing (PGT) has made it possible to block the inheritance of autosomal dominant polycystic kidney disease (ADPKD) as early as possible. However, we need to know the patients’ fertility intentions and their acceptance of PGT.

Methods

A questionnaire survey was conducted to collect data on the basic demographic data, quality of life, social support, fertility willingness, and level of understanding of genetic testing for blocking the inheritance of ADPKD among patients aged 18–45 years in seven hospitals from January 2018 to December 2018. After verification, statistics were calculated.

Results

A total of 260 patients with ADPKD were interviewed, including 137males (52.7%) and 123 females (47.3%). The overall fertility willingness rate was low (n = 117, 45.0%). The proportion of married patients aged 25–34 years that were at the optimal reproductive age but did not yet have children was relatively high (n = 77, 67.0%). The fertility intentions of ADPKD patients were significantly influenced by age (OR: 0.101, 95% CI 0.045–0.225, P < 0.001) and education level (OR: 2.134, 95% CI 1.162–3.917, P = 0.014). Among patients who are willing to have children, 207 (79.6%) of them would choose PGT technology. Among those who were not sure whether they would choose PGT technology, the first major concern was technical safety (49.2%).

Conclusions

The reproductive desire of childbearing ADPKD patients in China was low. Strengthening the health education of ADPKD genetic knowledge and reducing the cost of related technologies may improve the fertility intentions and reduce the barriers to acceptance of PGT.

Preimplantation genetic testing for aneuploidy in poor ovarian responders with four or fewer oocytes retrieved

PURPOSE

To assess whether preimplantation genetic testing for aneuploidies (PGT-A) at the blastocyst stage improves clinical outcomes compared with transfer of embryos without PGT-A in poor ovarian response (POR) patients.

METHODS

Retrospective cohort study of IVF cycles from 2016 to 2019 at a single academic fertility center. IVF cycles with POR and four or fewer oocytes retrieved were stratified into PGT-A (n = 241) and non-PGT (n = 112) groups. In PGT-A cycles, trophectoderm biopsy, next-generation sequencing with 24-chromosome screening, and single euploid frozen embryo transfer were performed. In non-PGT cycles, fresh or frozen transfer of untested embryos on day 3 or 5 was performed. Main outcomes included live birth rate and miscarriage rate per retrieval.

RESULT(S)

Patients who underwent PGT-A cycles were significantly less likely to reach embryo transfer compared with those who underwent non-PGT cycles (13.7% vs 70.6%). The live birth rate per retrieval did not differ between the PGT-A and non-PGT groups (6.6% vs 5.4%). Overall, the miscarriage rate was low. The PGT-A group demonstrated a significantly lower miscarriage rate per retrieval (0.4% vs 3.6%) as well as per pregnancy (5.9% vs 40.0%) compared with the non-PGT group. The number needed to treat to avoid one clinical miscarriage was 31 PGT-A cycles.

CONCLUSION(S)

PGT-A did not improve live birth rate per retrieval in POR patients with four or fewer oocytes retrieved. PGT-A was associated with a lower miscarriage rate; however, a fairly large number of PGT-A cycles were needed to prevent one miscarriage.

A clinical counseling tool predicting supernumerary embryos after a fresh IVF cycle

PURPOSE

To identify factors predictive of having supernumerary embryos in a fresh IVF cycle and create a prediction model for clinical counseling.

METHODS

We utilized a multivariable Poisson regression to identify predictive factors and then entered these into a logistic regression model, calculating a risk index for each significant variable. The final model was tested using a receiver operating characteristic curve.

RESULTS

A total of 60,616 fresh transfer cycles were reported to the Society for Assisted Reproductive Technology in 2014. Of these, 47.17% produced supernumerary embryos. A multivariate Poisson regression identified factors predictive of having supernumerary embryos, with age and AMH being the most predictive. Clinical prediction models were developed with acceptable and excellent discrimination. 23.5% of our cohort did not achieve a live birth following their fresh transfer and had excess embryos cryopreserved for future attempts.

CONCLUSION

Our study suggests that in a minority of fresh IVF cycles in the USA, the fresh transfer is not successful, and there are excess embryos cryopreserved for future use. The likelihood of excess embryos beyond those that would be transferred can be predicted with satisfactory precision prior to initiation of the cycle and with improved precision after fresh embryo transfer. Providing patients with a realistic estimate of their chances of having excess embryos at an initial IVF consult especially those with suspected poor prognosis can be beneficial in determining whether to proceed with multiple embryo banking cycles as opposed to proceeding with a fresh transfer, and whether to opt for an enhanced embryo selection technique such as preimplantation genetic testing for aneuploidy (PGT-A).

Comprehensive analysis of the associations between previous pregnancy failures and blastocyst aneuploidy as well as pregnancy outcomes after PGT-A

PURPOSE

To investigate the associations of previous pregnancy failures, including implantation failures (IFs), biochemical pregnancy losses (BPLs), and early (EMs) and late miscarriages (LMs), with blastocyst aneuploidy and pregnancy outcomes after PGT-A.

METHODS

This study included 792 couples who underwent PGT-A after multiple pregnancy failures. Subgroup analyses were used to compare the blastocyst aneuploidy rate (BAR), implantation rate (IR), early miscarriage rate (EMR), and live birth rate (LBR). Multiple linear and logistic regression models were used to evaluate the associations. The control group comprised couples with ≤ 2 IFs, ≤ 1 BPL, ≤ 1 EM, and no LM.

RESULTS

Notably, a history of ≥ 4 IFs was significantly associated with an increase in aneuploid blastocysts (42.86% vs. 33.05%, P = 0.044, B = 10.23 for 4 IFs; 48.80% vs. 33.05%, P = 0.002, B = 14.43 for ≥ 5 IFs). Women with ≥ 4 prior EMs also harbored more aneuploid blastocysts (41.00% vs. 33.05%, P = 0.048; B = 9.23). Compared with the control group, women with ≥ 4 prior EMs had a significantly higher EMR (6.58% vs. 31.11%, P < 0.001, OR = 6.49) and a lower LBR (53.49% vs. 34.18%, P = 0.007, OR = 0.56) after euploid transfer. Moreover, a history of LM(s) was associated with adverse pregnancy outcomes after PGT-A (OR for EM = 3.16; OR for live birth = 0.48). However, previous BPLs and 2 EMs were not associated significantly with blastocyst aneuploidy and pregnancy outcomes after PGT-A.

CONCLUSION

A history of high-order IFs or EMs and existence of LM(s) were significantly associated with blastocyst aneuploidy and adverse pregnancy outcomes after PGT-A, whereas no such associations were observed with BPLs or 2 EMs.

Preimplantation genetic testing in assisted reproduction technology

A significant proportion of clinically recognized pregnancies end in miscarriage. About 50 % of early pregnancy losses are due to chromosome abnormalities. In assisted reproduction technology (ART), a high proportion of top-quality embryos with morphological values are aneuploid whenever they have been evaluated in terms of genetic integrity in human preimplantation embryos either from in vitro or in vivo matured oocytes. It is plausible to think of preimplantation genetic testing (PGT) as a means of increasing pregnancy rates and minimizing the risk of fetal aneuploidy. It is believed that PGT will assume a prominent role in the field of ART, especially in a successful pregnancy, so it is embraced recently as a popular diagnostic technique. The PGT includes three sub-categories of PGT for aneuploidies (PGT-A), PGT for single gene / monogenic disorders (PGT-M), and PGT for chromosome structural rearrangements (PGT-SR). PGT-A is used to detect aneuploidies and previously it was known as PGS. PGT-M, formerly known as PGD, is intended to reduce monogenic defects. Previously known as PGS translocation, PGT-SR is PGT to identify structural chromosomal rearrangements. Since many of the old and new definitions for PGT are still vague and confusing for some researchers in the field of reproductive genetics, the main purpose of this study is to introduce all PGT classifications as well as elaborate on different aspects of this technology to improve ART outcomes.

Is cell-free DNA in spent embryo culture medium an alternative to embryo biopsy for preimplantation genetic testing? A systematic review

Preimplantation genetic testing (PGT) is increasingly used worldwide. It currently entails the use of invasive techniques, i.e. polar body, blastomere, trophectoderm biopsy or blastocentesis, to obtain embryonic DNA, with major technical limitations and ethical issues. Evidence suggests that invasive PGT can lead to genetic misdiagnosis in the case of embryo mosaicism, and, consequently, to the selection of affected embryos for implantation or to the destruction of healthy embryos. Recently, spent culture medium (SCM) has been proposed as an alternative source of embryonic DNA. An increasing number of studies have reported the detection of cell-free DNA in SCM and highlighted the diagnostic potential of non-invasive SCM-based PGT for assessing the genetic status of preimplantation human embryos obtained by IVF. The reliability of this approach for clinical applications, however, needs to be determined. In this systematic review, published evidence on non-invasive SCM-based PGT is presented, and its current benefits and limitations compared with invasive PGT. Then, ways of optimizing and standardizing procedures for non-invasive SCM-based PGT to prevent technical biases and to improve performance in future studies are discussed. Finally, clinical perspectives of non-invasive PGT are presented and its future applications in reproductive medicine highlighted.

Novel intronic variant in PALB2 gene and effective prevention of Fanconi anemia in family

Despite the acceptance of NextGen sequencing as a diagnostic modality suitable for probands and carriers of Mendelian diseases, its efficiency in identifying causal mutations is limited by both technical aspects of variant call algorithms and by imperfect, consensus-based criteria for assessing the pathogenicity of the findings. Here we describe the medical history of the family with a child born with Fanconi anemia. In this case, typical diagnostic routines were complicated by unusual combination of mutations. PALB2 variant NM_024675.3:c.172_175delTTGT (p.Gln60Argfs) in maternal sample, previously classified as a definitely pathogenic frameshift mutation, was in compound heterozygous state with PALB2 NM_024675.3:c.3114-16_3114-11del (p.Asn1039Glyfs*7), which led to validated PALB2 exon 11 skipping event in paternal locus. Findings enabled the development of the PGТ and successful selection of two mutation-free embryos. We show that even in absence of definitive exome findings, clinician-guided research inquiries into the structure and function of the suspected loci allow definitive diagnosis. Described case provides an example of a crucial input of an investigational workflow in genetic prognosis and successful PGT.

A tale of two studies: now is no longer the best of times for preimplantation genetic testing for aneuploidy (PGT-A)

Preimplantation genetic testing for aneuploidy (PGT-A) does not create normal embryos, but selecting a viable embryo for a fresh transfer has the potential to deliver an extra effect for live birth from a stimulated cycle by evading the attrition associated with embryo cryopreservation. Improved genetic tests are now available for selecting viable embryos; however, current embryo cryopreservation techniques also have a superior survival rate, which means it is now possible to transfer most morphologically suitable embryos from a stimulated cycle one at a time. The cumulative live birth rate from a stimulated cycle is now unlikely to be superior compared with morphological assessment alone, with any benefit likely to be associated with a reduction in the risk of miscarriage and the time to pregnancy. This communication offers a perspective on the likely benefit and disbenefit of PGT-A based on the outcome of modern-day clinical studies. Caution should be advised regarding offering PGT-A to every woman. Quantifying the likely miscarriage benefit and live birth disbenefit for an appropriate patient group may help to better inform couples who might be considering adding aneuploidy screening to their treatment cycle.

Euploid rates among oocyte donors: is there an optimal age for donation?

PURPOSE

To examine cycle blastocyst euploid rates among age subgroups of oocyte donors.

METHODS

Retrospective cohort analysis of ova donation in vitro fertilization cycles (OD-IVF) for which trophectoderm biopsy for preimplantation genetic testing for aneuploidy (PGT-A) by array comparative genomic hybridization (aCGH) or next generation gene sequencing (NGS) was employed between January 2015 and December 2018 in a single high-volume fertility center.

RESULTS

Compared to oocyte donors age 26-30, oocyte donors age ≤ 25 had similar cycle blastocyst euploid rates (80 [66.7, 87.5]%, vs. 75 [62.5, 87.5]%, median [IQR], p = 0.07), blastocyst formation rates (66.7 [50, 75]%, vs. 62.5 [52, 75]%, p = 0.55), and number of retrieved oocytes (29 [23, 37] vs. 27 [20, 35], p = 0.18). Age of oocyte donor from 18 to 34 was not correlated with cycle blastocyst euploid rate.

CONCLUSION

Oocyte donors age ≤ 25 had similar cycle blastocyst euploid rates, blastocyst formation rates, and number of retrieved oocytes compared to donors age 26-30. There was no correlation between cycle blastocyst euploid rates and age of the oocyte donor from 18 to 34 years. Given the lack of significant age-related change in cycle blastocyst euploid rates, our data support existing practices which do not favor a specific age subgroup of young oocyte donors.

The First Live Birth in Lithuania After Application of Preimplantation Genetic Testing

Summary. Background.

Preimplantation genetic testing (PGT) is a genetic testing procedure that is performed before the implantation of embryos for the identification of genetic abnormalities. It is commonly performed when one or both expecting parents have such abnormalities and are at a high risk of passing them to their offspring. The aim of this case report is to describe the first successful IVF/ICSI/PGT procedure in Lithuania.

Case report.

A 27-year-old woman and a 31-year-old man, a married couple, were referred to VUHSK Santaros Fertility Center after trying to conceive for 4 years. In a previous relationship, the woman got pregnant spontaneously and decided to terminate the pregnancy. The husband does not have any children. During the medical examination, the transvaginal ultrasound revealed a low antral follicle count and low anti-Müllerian hormone level for the woman. Semen analysis for the male patient showed severe oligoastenospermia, which confirmed the previous abnormal spermogram results. Chromosome analysis revealed normal karyotype for the woman (46,XX) and Robertsonian translocation for the husband (45,XY,der(13;14)(q10;q10)). After the interdisciplinary medical team counselling, an ICSI with PGT-SR was suggested for the couple. The woman underwent controlled ovarian hyperstimulation with GnRH antagonist protocol for 11 days. Only one embryo with no unbalanced rearrangements was identified and transferred to the woman. On the 14^th day post oocyte retrieval, the first serum β-hCG result was received – 39.5 mIU/ml, and the normal gestational sac at 5 weeks and 3 days was confirmed by ultrasound examination.

Conclusion:

the first successful pregnancy was achieved in Lithuania and the first IVF/ICSI/PGT-SR newborn in Lithuania was born in 2019 – a vaginal birth of a healthy girl with gestational age of 38 weeks and 4 days and a weight of 2820 g; the Apgar score was 10/10. The IVF/ICSI/PGT procedure was successfully implemented by the multidisciplinary team in VUHSK.

Outcomes of Preimplantation Genetic Testing for Single Gene Defects in a Privately Funded Period and Publicly Funded Period: A North-American Single Center Experience

BACKGROUND

The purpose of this study was to assess whether the outcomes from IVF-preimplantation genetic testing (IVF-PGT) cycles for single gene defects (SGD) (PGT-M) differ between a privately funded period (PRP) and publicly funded period (PUP).

METHODS

A retrospective cohort study was conducted in a North-American single tertiary center. The PRP (March 1998 to July 2010) comprised 56 PGT-M cycles from 58 IVF cycles in 38 couples, and the PUP (August 2010 to May 2015) comprised 59 PGT-M cycles from 87 IVF cycles in 38 couples. One PGT-M cycle is defined as one biopsy procedure from one or serial IVF cycles. A p-value of 0.05 was considered statistically significant.

RESULTS

The clinical pregnancy rates (CPR) per PGT-M cycle were 30.4% and 52.5% in each period, respectively (p=0.021). The live birth rates (LBR) per PGT-M cycle were 21.5% versus 40.9% in each period, respectively (p=0.037). A sub-analysis within the PUP comparing 39 PGT-M cycles from 39 IVF cycles with 20 PGT-M cycles from 49 IVF cycles yielded CPRs per PGT-M cycle of 64.1% and 30.0% and LBRs per PGT-M cycle of 53.8% and 15.0%, in each group, respectively (p< 0.05 for both).

CONCLUSION

The transition from private to public funding and a single embryo transfer (ET) guideline has little impact on embryological and clinical outcomes of PGT-M cycles, and results in lower rates of multiple pregnancies. However, these two systems may serve different populations.

The mechanisms and clinical application of mosaicism in preimplantation embryos

Embryos containing distinct cell lines are referred to as mosaic embryos, which are considered to be caused by mitotic errors in chromosome segregation during preimplantation development. As the accuracy and resolution of detection techniques improve, more and more mosaic embryos were identified recently. The impacts of mosaic embryos on survival and potential pregnancy outcome have been reported to be diverse in different studies. Because of the universality and clinical significance of mosaicism, it is essential to unravel the mechanisms and consequences with regard to this phenomenon in human pre- and post-implantation embryos. The purpose of this review is to explore the mechanisms, causes of mosaicism, and the development of pre- and post-implantation mosaic embryos in the light of recent emerging data, with the aim of providing new references for clinical applications.

Chromosomal segregation in sperm of the Robertsonian translocation (21;22) carrier and its impact on IVF outcome

PURPOSE

To assess the variability of meiotic segregation patterns in sperm of Robertsonian translocation (RobT) carrier t(21;22) and present effect on reproductive outcome.

METHODS

Infertile couple enrolled in IVF/ICSI program. Sperm chromosomal segregation analysis was done using FISH; preimplantation genetic testing for aneuploids (PGT-A) was performed by NGS.

RESULTS

Patients had a low fertilization rate and a negative outcome after the first IVF/ICSI cycle, so they were advised to do chromosomal aberration analysis before their next attempt. The second IVF/ICSI procedure resulted in pregnancy, and two blastocysts were cryopreserved. The NIFTY test has shown low risk for all tested trisomies, sex chromosomes aneuploidis, and deletion syndromes, so a healthy female child was born. During pregnancy, karyotypisation results revealed that the male partner is a RobT carrier t(21;22). Sperm segregation analysis of chromosomes 21 and 22 has shown six types of sperm chromosome sets. The majority of sperm cells had a normal/balanced RobT form of a haploid set of chromosomes (68.5-76%) called an "alternate." Sperm cells that had additional chromosome 21 or 22, or lack of chromosome 21 or 22, were present in 4-12%. PGT-A performed on two cryopreserved blastocysts revealed one embryo euploid and the other with the mosaic aneuploidy of chromosome 7 present in 50% of the cells.

CONCLUSION

Infertile couples with a RobT male carrier who have semen comprising of normal/alternate form in the majority have a good prognosis of IVF/ICSI outcome. PGT is recommended because of the possible occurrence of viable trisomic embryos and potential interchromosomal effect.

Analysis of molecular cytogenetic features and PGT-SR for two infertile patients with small supernumerary marker chromosomes

RESEARCH QUESTION

Can preimplantation genetic testing for structural rearrangement (PGT-SR) with next-generation sequencing (NGS) be used to infertile patients carrying small supernumerary marker chromosomes (sSMCs)?

DESIGN

In this study, two infertile patients carrying ring sSMCs were recruited. Different molecular cytogenetic techniques were performed to identify the features of the two sSMCs, followed by clinical PGT-SR cycles.

RESULTS

The results of G-banding and FISH showed that patient 1's sSMC originated from the 8p23-p10 region, with a resulting karyotype of [ 47,XY, del(8)(p23p10), +r(8)(p23p10).ish del(8)(CEP8+,subtle 8p+,subtle 8q+),r(8)(CEP8+,subtle 8p-,subtle 8q-)[55/60].arr(1-22) ×2,(X,Y)×1]. The sSMC of patient 2 was derived from chromosome 3 and further microdissection with next-generation sequencing (MicroSeq) revealed it contained the region of chromosome 3 between 93,504,855 and 103,839,892 bp (GRCh37), which involved 52 known genes. So the karyotype of patient 2 was 47,XX, +mar.ish der(3)(CEP3+,subtle 3p-,subtle 3q-)[49/60].arr[GRCh37] 3q11.2q13.1(93,500,001_103,839,892) ×3(0.5). PGT-SR with NGS was performed to provide reproductive guidance for the two patients. For patient 1, four balanced euploid embryos and four embryos with partial trisomy/monosomy of (8p23.1-8p11.21) were obtained, and a balanced euploid embryo was successfully implanted and had resulted in a healthy baby. For patient 2, an embryo with monosomy of sex chromosomes and another embryo with a duplication at (3q11-q13.1), neither of which was available for implantation.

CONCLUSIONS

The identification of the origins and structural characteristics of rare sSMCs should rely on different molecular cytogenetic techniques. PGT-SR is an alternative fertility treatment for these patients carrying sSMCs. This study may provide directions for the assisted reproductive therapy for infertile patients with sSMC.

Targeting myotonic dystrophy by preimplantation genetic diagnosis-karyomapping

OBJECTIVE

To report a case with Myotonic dystrophy type I with successful preimplantation genetic diagnosis-karyomapping.

CASE REPORT

A 34-year-old female carrier of myotonic dystrophy type I was treated at our clinic with a successful pregnancy after preimplantation genetic testing for monogenic disorders using karyomapping of her blastocysts.

CONCLUSION

Myotonic dystrophy type I is an inherited autosomal dominant disease producing various neuromuscular disturbances. Offspring of carriers have a 50% chance of carrying CTG repeat sequences in the DMPK gene, and various time-consuming methodologies have been developed for genetic diagnosis. With a novel, efficient, and precise method by karyomapping using single nucleotide polymorphism arrays to diagnose single gene disorders, one could terminate the transmission of single gene disorder. Herein, we reported a 34-year-old female carrier of myotonic dystrophy type I achieve a successful pregnancy after preimplantation genetic testing for monogenic disorders using karyomapping method of her blastocysts.

Less-invasive chromosome screening of embryos and embryo assessment by genetic studies of DNA in embryo culture medium

PURPOSE

To perform a preliminary exploration of a new embryo rank in clinical practice by combining the embryo chromosome copy number and mitochondrial copy number analysis of DNA extracted from embryo culture medium and blastocoel fluid.

METHOD

Eighty-three ICSI embryos from day 2 or day 3 were cultured to day 5 or day 6. Thirty-two blastocysts of 3 cc or above were obtained. Culture medium and blastocoel fluid were collected at 24 h before blastocyst formation. The genomic DNA and mitochondrial DNA (mtDNA) from the culture medium combined with blastocoel fluid and the whole blastocyst were amplified and sequenced by MALBAC-NGS. We compared the chromosomal information generated by the new protocol from the culture medium and the information employed by the whole embryo method. A multivariable linear regression was performed to study the impact of the blastocyst morphological score, chromosomal abnormality, embryo mtDNA copy number, and female age on the culture medium mtDNA copy number.

RESULTS

(1) The DNA from 31 blastocysts was successfully amplified, and the successful amplification rate was 96.9% (31/32). The success rate of the amplification of genomic DNA extracted from the culture medium was 87.5% (28/32). (2) There were 18 blastocysts in which the less invasive method and the whole embryo method revealed the same results. The consistency rate was 66.7% (18/27). (3) The culture medium mitochondrial DNA copy number (MCN) had a significantly positive correlation with the blastocyst mitochondrial DNA copy number (P = 0.001), female age (P = 0.012), and blastocyst score (P = 0.014), but there was no obvious correlation with blastocyst chromosome (P = 0.138).

CONCLUSIONS

The preliminary exploration result of the less invasive approach for having an embryo rank was not satisfying, which still awaits further long-term evaluation.

Preimplantation Genetic Testing for Aneuploidy Improves Clinical, Gestational, and Neonatal Outcomes in Advanced Maternal Age Patients Without Compromising Cumulative Live-Birth Rate

PURPOSE

To report the effects of blastocyst stage aneuploidy testing on clinical, gestational, and neonatal outcomes for patients of advanced maternal age undergoing IVF.

METHODS

This is a single-center observational-cohort study with 2 years follow-up. The study includes a total of 2538 couples undergoing 2905 egg collections (control group), 308 (PGT-A), and 106 (drop-out group, consenting for PGT-A but withdrawing due to poor embryological outcome) RESULTS: Compared with control group, PGT-A showed improved clinical outcomes (live-birth rate per transferred embryo, LBR 40.3% vs 11.0%) and reduced multiple pregnancy rate (MPR, 0% vs 11.1%) and pregnancy loss (PL, 3.6% vs 22.6%). Drop-out group showed the worst clinical outcomes suggesting that abandoning PGT-A due to poor response to ovarian stimulation is not a favorable option. Cytogenetic analysis of product of conceptions and CVS/amniocentesis showed higher aneuploid pregnancy rates for control group regardless of embryo transfer strategy (0%, 17.9%, and 19.9%, for PGT-A, control day 5 and day 3, respectively). Multivariate analysis showed no negative impact of PGT-A-related interventions on cumulative delivery rate (26.3%, 95% CI 21.5-31.6 vs 24.0%, 95% CI 22.5-25.6 for PGT-A and control, respectively) and on neonatal outcomes.

CONCLUSION

PGT-A improves clinical outcomes, particularly by reducing pregnancy loss and chromosomally abnormal pregnancy for patients of advanced maternal age, with no major impact on cumulative live-birth rate (CLBR) per egg retrieval.

Preimplantation genetic testing for a family with usher syndrome through targeted sequencing and haplotype analysis

Background

Preimplantation genetic testing for monogenic defects (PGT-M) has been available in clinical practice. This study aimed to validate the applicability of targeted capture sequencing in developing personalized PGT-M assay.

Methods

One couple at risk of transmitting Usher Syndrome to their offspring was recruited to this study. Customized capture probe targeted at USH2A gene and 350 kb flanking region were designed for PGT-M. Eleven blastocysts were biopsied and amplified by using multiple displacement amplification (MDA) and capture sequencing. A hidden Markov model (HMM) assisted haplotype analysis was performed to deduce embryo’s genotype by using single nucleotide polymorphisms (SNPs) identified in each sample. The embryo without paternal rare variant was implanted and validated by conventional prenatal or postnatal diagnostic means.

Results

Four embryos were diagnosed as free of father’s rare variant, two were transferred and one achieved a successful pregnancy. The fetal genotype was confirmed by Sanger sequencing of fetal genomic DNA obtained by amniocentesis. The PGT-M and prenatal diagnosis results were further confirmed by the molecular diagnosis of the baby’s genomic DNA sample. The auditory test showed that the hearing was normal.

Conclusions

Targeted capture sequencing is an effective and convenient strategy to develop customized PGT-M assay.

Pregnancy outcomes of reciprocal translocation carriers with two or more unfavorable pregnancy histories: before and after preimplantation genetic testing

PURPOSE

To report the normal live birth and birth defect rates pre- and post- preimplantation genetic testing for chromosomal structural rearrangements (PGT-SR) in reciprocal translocation carriers who have experienced two or more unfavorable pregnancy histories.

METHODS

We conducted a retrospective cohort study of 194 couples who underwent 265 PGT-SR cycles between January 2013 and August 2016. The rates of miscarriage, normal live birth, and birth defect pre- and post- PGT-SR treatment were recorded. The types of birth defect were also categorized.

RESULTS

Before PGT-SR treatment, the 194 couples with reciprocal translocation had a previous reproductive history consisting of 592 pregnancies in total: 496 (83.8%) were miscarriages; 29 (4.9%) ended by induced abortion due to unintended pregnancy; 36 (6.1%) had birth defects; and 17 (2.9%) were normal live births. After PGT-SR treatment, there were 118 clinical pregnancies. Of these pregnancies, 13 (11.0%) were miscarriages, 101 (85.6%) were normal live births, and 4 (3.4%) had birth defects. In total, 14 different disorders were noted in the prenatal and postnatal examinations. Before the PGT-SR treatment, multiple birth defects, central nervous system abnormalities, and congenital heart defects were the three most common congenital malformations. Excluding for methylmalonic acidemia, there were only single and mild birth defects after the PGT-SR treatment.

CONCLUSIONS

After the PGT-SR treatment, the reciprocal translocation carriers who had previously experienced two or more unfavorable pregnancy outcomes had a low risk of miscarriages and birth defects. The rate of normal live births per pregnancy was higher after PGT-SR treatment.

Effects of a carrier's sex and age on the segregation patterns of the trivalent of Robertsonian translocations

PURPOSE

To investigate the effects of a carrier's sex and age on the segregation patterns of the trivalent of Robertsonian translocations.

METHODS

This retrospective study was designed to analyze the segregation patterns of the trivalent and euploidy rates of blastocysts. Data were collected from 154 couples with Robertsonian translocation (77 with a female carrier and 77 with a male carrier). Embryos were diagnosed via array comparative genomic hybridization between January 2013 and July 2017. The segregation patterns of the trivalent of 604 blastocysts were analyzed according to the carrier's sex and age.

RESULTS

The proportion of alternate segregation was significantly higher (82.9% vs. 55.2%) in the male carriers than in the female carriers of Robertsonian translocation, and the proportion of adjacent segregation was significantly lower (16.8% vs. 42.6%), with no difference in 3:0 segregation. The segregation patterns were similar in same-sex carriers when analyzed according to the type of translocation. The carrier's age had no influence on the segregation patterns of the trivalent.

CONCLUSIONS

The proportions of the trivalent's meiotic segregation pattern differ significantly according to the carrier's sex in Robertsonian translocations and are independent of the carrier's age. A significantly higher proportion of alternate segregation for normal or balanced chromosome contents was observed in the blastocysts of the male carriers than in those of the female carriers.

Maternal and neonatal outcomes associated with trophectoderm biopsy

OBJECTIVE

To assess whether pregnancies achieved with trophectoderm biopsy for preimplantation genetic testing (PGT) have different risks of adverse obstetric and neonatal outcomes compared with pregnancies achieved with IVF without biopsy.

DESIGN

Observational cohort.

SETTING

University-affiliated fertility center.

PATIENT(S)

Pregnancies achieved via IVF with PGT (n = 177) and IVF without PGT (n = 180) that resulted in a live birth.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Maternal outcomes including preeclampsia and placenta previa and neonatal outcomes including birth weight and birth defects.

RESULT(S)

There was a statistically significant increase in the risk of preeclampsia among IVF+PGT pregnancies compared with IVF without PGT pregnancies, with an incidence of 10.5% versus 4.1% (adjusted odds ratio [aOR] = 3.02; 95% confidence interval [95% CI], 1.10, 8.29). The incidence of placenta previa was 5.8% in IVF+PGT pregnancies versus 1.4% in IVF without PGT pregnancies (aOR = 4.56; 95% CI, 0.93, 22.44). Similar incidences of gestational diabetes, preterm premature rupture of membranes, and postpartum hemorrhage were observed. IVF+PGT and IVF without PGT neonates did not have a significantly different gestational age at delivery or rate of preterm birth, low birth weight, neonatal intensive care unit admission, neonatal morbidities, or birth defects. All trends, including the significantly increased risk of preeclampsia in IVF+PGT pregnancies, persisted upon stratification of analysis to only singleton live births.

CONCLUSION(S)

To date, this is the largest and most extensively controlled study examining maternal and neonatal outcomes after trophectoderm biopsy. There was a statistically significant three-fold increase in the odds of preeclampsia associated with trophectoderm biopsy. Given the rise in PGT use, further investigation is warranted.

A prospective study of non-invasive preimplantation genetic testing for aneuploidies (NiPGT-A) using next-generation sequencing (NGS) on spent culture media (SCM)

PURPOSE

This study was to evaluate if spent culture media (SCM) of embryos could be used as a non-invasive tool to achieve aneuploidy screening. Ploidy calls, as well as concordance rates between PGT-A results from trophectoderm (TE) and SCM, were compared. Clinical outcomes of single euploid transfers were also evaluated.

METHODS

The study was conducted from March 2017 to June 2018 in a university-based ART center. SCM of day 3 to the day(s) of TE biopsy of all biopsied blastocysts were collected for testing. PGT-A results of SCM were compared with the standard results of TE, with clinical relevance and outcomes examined.

RESULTS

NiPGT-A using SCM gave a sensitivity of 81.6%, specificity of 48.3%, positive predictive value of 82.6%, and negative predictive value of 46.7% in ploidy calling. The concordance rates for autosomes and sex determination were 62.1% and 82.4%, respectively. There were 14 single embryo transfer cycles of euploids as determined by TE biopsy. Clinical outcomes not only confirmed 3 false positive results from SCM but also reflected the true ploidy status of the transferred embryo in one case. If ploidy calls were dichotomized without mosaic embryos, the sensitivity and NPV would increase to 91.0% and 66.7% (p = 0.60 and p = 0.25), respectively.

CONCLUSIONS

Cell-free DNA found in SCM could provide ploidy information of an embryo as in PGT-A from its TE. Given its potential to reflect the comprehensive chromosomal profile of the whole embryo, more research based on clinical outcomes is required to determine if SCM could be a reliable selection tool in PGT-A.

Detection of a balanced translocation carrier through trophectoderm biopsy analysis: a case report

BACKGROUND

Balanced translocation carriers are burdened with fertility issues due to improper chromosome segregation in gametes, resulting in either implantation failure, miscarriage or birth of a child with chromosomal disorders. At the same time, these individuals are typically healthy with no signs of developmental problems, hence they often are unaware of their condition. Yet, because of difficulties in conceiving, balanced translocation carriers often turn to assisted reproduction, some of whom may also undergo preimplantation genetic testing for aneuploidy (PGT-A) to improve the likelihood of achieving a successful pregnancy.

CASE REPORT

We describe a female patient, who pursued in vitro fertilization (IVF) treatment coupled with PGT-A following two consecutive miscarriages, unaware of her genetic condition. PGT-A was performed on blastocyst-stage embryos and the results of comprehensive chromosome screening from a first IVF cycle demonstrated reciprocal segmental aberrations on chromosome 7 and chromosome 10 in two out of four embryos. Due to distinct embryo profiles, the couple was then referred for genetic counselling and subsequent parental karyotyping revealed the presence of a previously undetected balanced translocation in the mother.

CONCLUSIONS

These results confirm previous reports that genome-wide PGT-A can facilitate the identification of balanced translocation carriers in IVF patients, providing explanation for poor reproductive outcome and allowing adjustments in treatment strategies.

Live birth rate is associated with oocyte yield and number of biopsied and suitable blastocysts to transfer in preimplantation genetic testing (PGT) cycles for monogenic disorders and chromosomal structural rearrangements

Objectives

To investigate whether live birth (LB) is associated with oocyte yield and number of biopsied and suitable blastocyst to transfer following preimplantation genetic testing (PGT) for monogenic disorders (PGT-M) and chromosomal structural rearrangements (PGT-SR).

Study design

All couples underwent controlled ovarian stimulation, blastocyst biopsy, vitrification and transfer of suitable embryo(s) in a frozen embryo transfer (FET) cycle.

Results

Of 175 couples who underwent PGT treatment, 249 oocytes retrievals were carried out and 230 FET were subsequently undertaken. 122/230 (53%, 95% CI 47-59) FET resulted in a LB and 16/230 (7%, 95% CI 4-11) have resulted in ongoing pregnancies. 21/230 (9%, 95% CI 6-14) FET resulted in miscarriage and 69/230 (30%, 95% CI 24-36) concluded with failed implantation. Two (1%, 95% CI 0-3) transfers underwent termination for congenital malformation, with no evidence of misdiagnosis by prenatal testing. The relationship between number of oocytes retrieved and number of blastocysts biopsied and suitable embryos to transfer were significant (p = 0.00; Incidence rate ratio (IRR) 1.05; 95% 1.04-1.06; p = 0.00; IRR 1.04; 95%, 1.03-1.06), respectively. The number of oocytes collected (p = 0.007; OR 1.06; 95% CI 1.01-1.10), the number of blastocysts biopsied (p = 0.001; OR 1.14; 95% 95% CI 1.06-1.23) and the number of suitable embryos to transfer (p = 0.00; OR 1.38; 95% CI 1.17-1.64) were all significantly associated with the odds of achieving a LB. There is a 14% and 38% increased chance of a LB per additional blastocyst biopsied and suitable embryo to transfer, respectively.

Conclusions

PGT-M and PGT-SR outcomes are significantly associated with egg yield, number of blastocysts to biopsy and suitable embryos to transfer.