Preimplantation Genetic Testing: Its Evolution, Where Are We Today?

Updates in preimplantation genetic testing (PGT)

Preimplantation genetic testing (PGT) involves taking a biopsy of an early embryo created through in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI). Genetic testing is performed on the biopsy, in order to select which embryo to transfer. PGT began as an experimental procedure in the 1990s, but is now an integral part of assisted human reproduction (AHR). PGT allows for embryo selection which can reduce the risk of transmission of inherited disease and may reduce the chance of implantation failure and pregnancy loss. This is a rapidly evolving area, which raises important ethical issues. This review article aims to give a brief history of PGT, an overview of the current evidence in PGT along with highlighting exciting areas of research to advance this technology.

Transfer of embryos with positive PGT-M results: Genetic Counselors' perspectives and ethical considerations

Increasing numbers of fertility patients use preimplantation genetic testing for monogenic conditions (PGT-M) during in vitro fertilization (IVF). While PGT-M is primarily used to avoid implanting embryos with a monogenic condition, patients can request to transfer an embryo with the monogenic condition (positive embryo transfer), especially in cases where an IVF cycle results in no unaffected embryos. Transferring embryos with known disease-causing variants raises ethical concerns. There is limited understanding about how stakeholders in the assisted reproductive technology (ART) field approach these issues. In this study, genetic counselors were sent a survey to gather insight into their views about transferring embryos with different monogenic conditions. N = 99 genetic counselors completed the survey, 22 of whom had experience with patients requesting or deciding to transfer an embryo with a monogenic condition (positive embryo transfer experience). Most participants, including those with positive embryo transfer experience, were supportive of positive embryo transfer, regardless of the genetic condition. While participating genetic counselors were largely supportive of all patient decisions, they reported increased moral uneasiness around transferring embryos with life-limiting monogenic conditions, such as Huntington's disease. Further investigation into the experiences of genetic counselors who have experienced positive embryo transfer requests in practice can help delineate the ethical questions that ART providers face in this context and clarify how genetic counselors can contribute to establishing guidelines in the ART field.

Cancer risk and male Infertility: Unravelling predictive biomarkers and prognostic indicators

In recent years, there has been a global increase in cases of male infertility. There are about 30 million cases of male infertility worldwide and male reproductive health is showing rapid decline in last few decades. It is now recognized as a potential risk factor for developing certain types of cancer, particularly genitourinary malignancies like testicular and prostate cancer. Male infertility is considered a potential indicator of overall health and an early biomarker for cancer. Cases of unexplained male factor infertility have high levels of oxidative stress and oxidative DNA damage and this induces both denovo germ line mutations and epimutations due to build up of 8-hydroxy 2 deoxygunaosine abase which is highly mutagenic and also induces hypomethylation and genomic instability. Consequently, there is growing evidence to explore the various factors contributing to an increased cancer risk. Currently, the available prognostic and predictive biomarkers associated with semen characteristics and cancer risk are limited but gaining significant attention in clinical research for the diagnosis and treatment of elevated cancer risk in the individual and in offspring. The male germ cell being transcriptionally and translationally inert has a highly truncated repair mechanism and has minimal antioxidants and thus most vulnerable to oxidative injury due to environmental factors and unhealthy lifestyle and social habits. Therefore, advancing our understanding requires a thorough evaluation of the pathophysiologic mechanisms at the DNA, RNA, protein, and metabolite levels to identify key biomarkers that may underlie the pathogenesis of male infertility and associated cancer. Advanced methodologies such as genomics, epigenetics, proteomics, transcriptomics, and metabolomics stand at the forefront of cutting-edge approaches for discovering novel biomarkers, spanning from infertility to associated cancer types. Henceforth, in this review, we aim to assess the role and potential of recently identified predictive and prognostic biomarkers, offering insights into the success of assisted reproductive technologies, causes of azoospermia and idiopathic infertility, the impact of integrated holistic approach and lifestyle modifications, and the monitoring of cancer susceptibility, initiation and progression. Comprehending these biomarkers is crucial for providing comprehensive counselling to infertile men and cancer patients, along with their families.

Preimplantation genetic testing in the current era, a review

BACKGROUND

Preimplantation genetic testing (PGT), also referred to as preimplantation genetic diagnosis (PGD), is an advanced reproductive technology used during in vitro fertilization (IVF) cycles to identify genetic abnormalities in embryos prior to their implantation. PGT is used to screen embryos for chromosomal abnormalities, monogenic disorders, and structural rearrangements.

DEVELOPMENT OF PGT

Over the past few decades, PGT has undergone tremendous development, resulting in three primary forms: PGT-A, PGT-M, and PGT-SR. PGT-A is utilized for screening embryos for aneuploidies, PGT-M is used to detect disorders caused by a single gene, and PGT-SR is used to detect chromosomal abnormalities caused by structural rearrangements in the genome.

PURPOSE OF REVIEW

In this review, we thoroughly summarized and reviewed PGT and discussed its pros and cons down to the minutest aspects. Additionally, recent studies that highlight the advancements of PGT in the current era, including their future perspectives, were reviewed.

CONCLUSIONS

This comprehensive review aims to provide new insights into the understanding of techniques used in PGT, thereby contributing to the field of reproductive genetics.

Appropriate whole genome amplification and pathogenic loci detection can improve the accuracy of preimplantation genetic diagnosis for deletional α-thalassemia

Objective

To improve the accuracy of preimplantation genetic testing (PGT) in deletional α-thalassemia patients.

Design

Article.

Patients

fifty-two deletional α-thalassemia couples.

Interventions

Whole genome amplification (WGA), Next-generation sequencing (NGS) and PCR mutation loci detection.

Main outcome measures

WGA, Single nucleotide polymorphism (SNP) and PCR mutation loci detection results; Analysis of embryo chromosome copy number variation (CNV).

Results

Multiple Displacement Amplification (MDA) and Multiple Annealing and Looping-Based Amplification Cycles (MALBAC) methods for PGT for deletional α-thalassemia. Blastocyst biopsy samples (n = 253) were obtained from 52 deletional α-thalassemia couples. The results of the comparison of experimental data between groups MALBAC and MDA are as follows: (i) The average allele drop-out (ADO) rate, MALBAC vs. MDA = 2.27% ± 3.57% vs. 0.97% ± 1.4%, P=0.451); (ii) WGA success rate, MALBAC vs. MDA = 98.61% vs. 98.89%, P=0.851; (iii) SNP haplotype success rate, MALBAC vs. MDA = 94.44% vs. 96.68%, P=0.409; (iv) The result of SNP haplotype analysis is consistent with that of Gap-PCR/Sanger sequencing results, MALBAC vs. MDA = 36(36/72, 50%) vs. 151(151/181, 83.43%), P=0; (v) Valid SNP loci, MALBAC vs. MDA = 30 ± 9 vs. 34 ± 10, P=0.02; (vi) The mean CV values, MALBAC vs. MDA = 0.12 ± 0.263 vs. 0.09 ± 0.40, P=0.916; (vii) The average number of raw reads, MALBAC vs. MDA =3244259 ± 999124 vs. 3713146 ± 1028721, P=0; (viii) The coverage of genome (%), MALBAC vs. MDA = 5.02 ± 1.09 vs. 5.55 ± 1.49, P=0.008.

Conclusions

Our findings indicate that MDA is superior to MALBAC for PGT of deletional α-thalassemia. Furthermore, SNP haplotype analysis combined with PCR loci detection can improve the accuracy and detection rate of deletional α-thalassemia.

Does embryo biopsy, independent of vitrification, impact perinatal outcomes? An analysis of perinatal outcomes following preimplantation genetic testing biopsy in fresh and frozen embryo transfer cycles

Objective

To compare neonatal outcomes in pregnancies resulting from embryos that have undergone preimplantation genetic testing (PGT) biopsy compared with no biopsy in both fresh and frozen embryo transfers (ETs) and determine whether findings are mediated by multiple births.

Design

Retrospective cohort study.

Setting

Society of Assisted Reproductive Technologies-Clinical Outcomes Reporting System data, 2014-2015.

Patients

Autologous in vitro fertilization treatment cycles using fresh or frozen blastocyst ET, with or without PGT biopsy.

Interventions

Not applicable.

Main Outcome Measures

Large for gestational age (LGA), small for gestational age, and preterm delivery. Secondary outcomes included high birthweight, low birthweight, and clinical pregnancy measures. Outcomes were evaluated using log-binomial regression models with repeated measures. Models were used to estimate the controlled direct effects of biopsy on birth outcomes that were not mediated by multiple gestations.

Results

In fresh ET, biopsy was associated with an increase in LGA (relative risk [RR] 1.45, confidence interval [CI] 1.04-2.02) that persisted in the model mediated for multiple gestation (RR 1.36, 95% CI 1.01-1.83) but was not present in an analysis restricted to elective single ET (RR 0.99, 95% CI 0.91-1.09). In frozen ET, there were no differences in any of the primary outcomes after accounting for multiple gestations.

Conclusions

In a large multicenter database, there were no differences in neonatal outcomes after PGT biopsy in frozen ET cycles, and an increase in LGA was noted in fresh transfers that persisted even after accounting for multiple gestations but was not present in analysis restricted to elective single ET.

Advancements and Applications of Preimplantation Genetic Testing in In Vitro Fertilization: A Comprehensive Review

Preimplantation genetic testing (PGT) has become an integral component of assisted reproductive technology (ART), offering couples the opportunity to screen embryos for genetic abnormalities before implantation during in vitro fertilization (IVF). This comprehensive review explores the advancements and applications of PGT in IVF, covering its various types, technological developments, clinical applications, efficacy, challenges, regulatory aspects, and future directions. The evolution of PGT techniques, including next-generation sequencing (NGS) and comparative genomic hybridization (CGH), has significantly enhanced the accuracy and reliability of genetic testing in embryos. PGT holds profound implications for the future of ART by improving IVF success rates, reducing the incidence of genetic disorders, and mitigating the emotional and financial burdens associated with failed pregnancies and genetic diseases. Recommendations for clinicians, researchers, and policymakers include staying updated on the latest PGT techniques and guidelines, exploring innovative technologies, establishing clear regulatory frameworks, and fostering collaboration to maximize the potential benefits of PGT in assisted reproduction. Overall, this review provides valuable insights into the current state of PGT and its implications for the field of reproductive medicine.

Optimizing non-invasive preimplantation genetic testing: investigating culture conditions, sample collection, and IVF treatment for improved non-invasive PGT-A results

PURPOSE

This study aimed to optimize the non-invasive preimplantation genetic testing for aneuploidy (niPGT-A) in the laboratory by comparing two collection timing of the spent culture medium (SCM), two embryo rinsing protocols, and the use of conventional insemination instead of intracytoplasmic sperm injection (ICSI).

METHODS

Results of two embryo rinsing methods (one-step vs sequential) and SCM collected on day 5 vs day 6 after retrieval were compared against trophectoderm (TE) biopsies as reference. Results from day 6 SCM in cycles fertilized by conventional insemination were compared with PGT-A using ICSI.

RESULTS

The rate of concordance was higher in day 6 samples than in day 5 samples when the sequential method was used, in terms of total concordance (TC; day 6 vs day 5: 85.0% vs 60.0%, p = 0.0228), total concordance with same sex (TCS, 82.5% vs 28,0%, p < 0.0001), and full concordance with same sex (FCS, 62.5% vs 24.0%, p = 0.0025). The sequential method significantly out-performed the one-step method when SCM were collected on day 6 (sequential vs one-step, TC: 85.0% vs 64.5%, p = 0.0449; TCS: 82.5% vs 54.8%, p = 0.0113; FCS: 62.5% vs 25.8%, p = 0.0021). There was no significant difference in niPGT-A results between cycles fertilized by the conventional insemination and ICSI.

CONCLUSION

We have shown a higher concordance rate when SCM was collected on day 6 and the embryos were rinsed in a sequential manner. Comparable results of niPGT-A when oocytes were fertilized by conventional insemination or ICSI. These optimization steps are important prior to commencement of a randomized trial in niPGT-A.

Trophectoderm biopsy of blastocysts following IVF and embryo culture increases epigenetic dysregulation in a mouse model

STUDY QUESTION

Does trophectoderm biopsy (TEBx) of blastocysts for preimplantation genetic testing in the clinic affect normal placental and embryo development and offspring metabolic outcomes in a mouse model?

SUMMARY ANSWER

TEBx impacts placental and embryonic health during early development, with some alterations resolving and others worsening later in development and triggering metabolic changes in adult offspring.

WHAT IS KNOWN ALREADY

Previous studies have not assessed the epigenetic and morphological impacts of TEBx either in human populations or in animal models.

STUDY DESIGN, SIZE, DURATION

We employed a mouse model to identify the effects of TEBx during IVF. Three groups were assessed: naturally conceived (Naturals), IVF, and IVF + TEBx, at two developmental timepoints: embryonic day (E)12.5 (n = 40/Naturals, n = 36/IVF, and n = 36/IVF + TEBx) and E18.5 (n = 42/Naturals, n = 30/IVF, and n = 35/IVF + TEBx). Additionally, to mimic clinical practice, we assessed a fourth group: IVF + TEBx + Vitrification (Vit) at E12.5 (n = 29) that combines TEBx and vitrification. To assess the effect of TEBx in offspring health, we characterized a 12-week-old cohort (n = 24/Naturals, n = 25/IVF and n = 25/IVF + TEBx).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Our mouse model used CF-1 females as egg donors and SJL/B6 males as sperm donors. IVF, TEBx, and vitrification were performed using standardized methods. Placenta morphology was evaluated by hematoxylin-eosin staining, in situ hybridization using Tpbpa as a junctional zone marker and immunohistochemistry using CD34 fetal endothelial cell markers. For molecular analysis of placentas and embryos, DNA methylation was analyzed using pyrosequencing, luminometric methylation assay, and chip array technology. Expression patterns were ascertained by RNA sequencing. Triglycerides, total cholesterol, high-, low-, and very low-density lipoprotein, insulin, and glucose were determined in the 12-week-old cohort using commercially available kits.

MAIN RESULTS AND THE ROLE OF CHANCE

We observed that at E12.5, IVF + TEBx had a worse outcome in terms of changes in DNA methylation and differential gene expression in placentas and whole embryos compared with IVF alone and compared with Naturals. These changes were reflected in alterations in placental morphology and blood vessel density. At E18.5, early molecular changes in fetuses were maintained or exacerbated. With respect to placentas, the molecular and morphological changes, although different compared to Naturals, were equivalent to the IVF group, except for changes in blood vessel density, which persisted. Of note is that most differences were sex specific. We conclude that TEBx has more detrimental effects in mid-gestation placental and embryonic tissues, with alterations in embryonic tissues persisting or worsening in later developmental stages compared to IVF alone, and the addition of vitrification after TEBx results in more pronounced and potentially detrimental epigenetic effects: these changes are significantly different compared to Naturals. Finally, we observed that 12-week IVF + TEBx offspring, regardless of sex, showed higher glucose, insulin, triglycerides, lower total cholesterol, and lower high-density lipoprotein compared to IVF and Naturals, with only males having higher body weight compared to IVF and Naturals. Our findings in a mouse model additionally support the need for more studies to assess the impact of new procedures in ART to ensure healthy pregnancies and offspring outcomes.

LARGE SCALE DATA

Data reported in this work have been deposited in the NCBI Gene Expression Omnibus under accession number GSE225318.

LIMITATIONS, REASONS FOR CAUTION

This study was performed using a mouse model that mimics many clinical IVF procedures and outcomes observed in humans, where studies on early embryos are not possible.

WIDER IMPLICATIONS OF THE FINDINGS

This study highlights the importance of assaying new procedures used in ART to assess their impact on placenta and embryo development, and offspring metabolic outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by a National Centers for Translational Research in Reproduction and Infertility grant P50 HD068157-06A1 (M.S.B., C.C., M.M.), Ruth L. Kirschstein National Service Award Individual Postdoctoral Fellowship F32 HD107914 (E.A.R.-C.) and F32 HD089623 (L.A.V.), and National Institutes of Health Training program in Cell and Molecular Biology T32 GM007229 (C.N.H.). No conflict of interest.

Comprehensive Review of Anesthetic Evaluation and Management in Obese Female Patients Undergoing In Vitro Fertilization

Obesity has become a global health epidemic with profound implications for various medical specialties, including reproductive medicine. This comprehensive review focuses on the anesthetic evaluation and management of obese patients undergoing in vitro fertilization (IVF) procedures. Obesity, as defined by BMI, is associated with infertility and poses unique challenges for anesthetic care. The review also addresses the timing of anesthesia concerning IVF procedures, the impact of obesity on IVF success rates, and the importance of emotional and psychological support for obese patients undergoing IVF. Challenges and future directions in the field are highlighted, focusing on ongoing research, emerging technologies, and the role of multidisciplinary teams in managing these complex cases. In conclusion, this review underscores the critical role of tailored anesthesia and perioperative care in optimizing outcomes for obese patients undergoing IVF. It provides valuable insights for anesthetic providers, reproductive specialists, and healthcare teams, emphasizing the need for a patient-centered approach to address the unique challenges posed by obesity in the context of assisted reproductive technology.

Mitochondrial epigenetic modifications and nuclear-mitochondrial communication: A new dimension towards understanding and attenuating the pathogenesis in women with PCOS

Mitochondrial DNA (mtDNA) epigenetic modifications have recently gained attention in a plethora of complex diseases, including polycystic ovary syndrome (PCOS), a common cause of infertility in women of reproductive age. Herein we discussed mtDNA epigenetic modifications and their impact on nuclear-mitochondrial interactions in general and the latest advances indicating the role of mtDNA methylation in the pathophysiology of PCOS. We highlighted epigenetic changes in nuclear-related mitochondrial genes, including nuclear transcription factors that regulate mitochondrial function and may be involved in the development of PCOS or its related traits. Additionally, therapies targeting mitochondrial epigenetics, including time-restricted eating (TRE), which has been shown to have beneficial effects by improving mitochondrial function and may be mediated by epigenetic modifications, have also been discussed. As PCOS has become a major metabolic disorder and a risk factor for obesity, cardiometabolic disorders, and diabetes, lifestyle/behavior intervention using TRE that reinforces feeding-fasting rhythms without reducing caloric intake may be a promising therapeutic strategy for attenuating the pathogenesis. Furthermore, future perspectives in the area of mitochondrial epigenetics are described.

The far-reaching impact of abortion bans: reproductive care and beyond

On 24 June 2022, the US Supreme Court overturned Roe v. Wade, a 49-year-old precedent that provided federal constitutional protection for abortions up to the point of foetal viability, returning jurisdiction to the individual states. Restrictions that came into effect automatically in several states, and are anticipated in others, will severely limit access to abortions in approximately half of the US. Even though every state allows for exceptions to the abortion bans, in some instances these exceptions can be used to preserve the health of a pregnant patient, while in other instances, only to preserve their life. The vague and confusing nature of the abortion ban exceptions threatens to compromise the standard of care for patients with pregnancy complications that are distinct from abortions, such as nonviable pregnancies, miscarriages, and ectopic pregnancies. Additionally, we envision challenges for the treatment of women with certain autoimmune conditions, pregnant cancer patients, and patients contemplating preimplantation genetic diagnosis as part of assisted reproductive technologies. The abortion ban exceptions will impact and interfere with the medical care of pregnant and non-pregnant patient populations alike and are poised to create a medical and public health crisis unlike any other one from the recent past.

De novo variants and recombination at 4q35: Hints for preimplantation genetic testing in facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) has been associated with the deletion of an integral number of 3.3 kb units of the polymorphic D4Z4 repeat array at 4q35. The prenatal identification of this defect can be carried out on chorionic villi or amniocytes, whereas preimplantation genetic testing for monogenic disorders (PGT-M) requires molecular markers linked to the D4Z4 allele of reduced size. In this context the reliability of this association is crucial. To test the informativeness of the nearby polymorphic markers we investigated recombination at 4q35 using the polymorphic markers D4S1523, D4S163 and D4S139 positioned at 0.55, 0.5 and 0.21 Mb proximal to the D4Z4 array respectively. We determined the probability of recombination events to occur in the D4Z4-D4S1523 interval considering 86 subjects belonging to 12 FSHD families and found a recombination frequency of 14% between D4Z4 and D4S1523. Our study also revealed the occurrence of de novo variants and germline mosaicism. These findings highlight the recombinogenic nature of the 4q subtelomere and indicate that caution should be taken when interpreting PGT-M results. It is advisable that a woman who underwent a PGT-M cycle undertakes a prenatal DNA analysis to confirm the size of the D4Z4 alleles carried by the fetus.

PGT pregnancies have a similar risk for post-partum complications as naturally conceived pregnancies

RESEARCH QUESTION

Do preimplantation genetic testing (PGT) pregnancies have higher post-partum complications compared with naturally conceived pregnancies?

DESIGN

Retrospective cohort study conducted in 2008-2020 at the Shaare Zedek Medical Center (SZMC), including all patients aged 18-45 years old who conceived following PGT with a singleton live birth >24 weeks. Data were collected from computerized hospital databases and patient files. There were two control groups: (i) pregnancies following IVF-ICSI (intracytoplasmic sperm injection); (ii) four neighbourhood controls for each case delivery (two women delivered before and two after) of women with naturally conceived pregnancies.

RESULTS

Overall, 120 PGT, 779 IVF-ICSI and 3507 naturally conceived deliveries were included. Demographic variables were similar apart from slightly higher age in the PGT (P = 0.003) and ICSI (P = 0.002) groups (31.07 ± 4.38 PGT, 31.66 ± 5.03 ICSI, 28.77 ± 5.72 naturally conceived). Composite post-partum placental-related complications (manual lysis of placenta, revision of uterine cavity, haemoglobin drop ≥3 g/dl, post-partum haemorrhage, need for blood transfusion) were more prevalent in both the PGT and IVF-ICSI groups as opposed to naturally conceived (20.0% versus 18.9% versus 10.3%, respectively, P < 0.001, P = 0.007). In a multivariate regression model PGT was not found to be independently associated with composite post-partum placental-related complications (adjusted odds ratio [aOR] 1.44, 95% confidence interval [CI] 0.83-2.15), while IVF-ICSI pregnancies had increased risk (aOR 1.52, 95% CI 1.20-1.97) compared with natural conception. No difference was found between fresh and frozen cycles or between day 3 and day 5 embryo transfer.

CONCLUSIONS

PGT pregnancies have a comparable risk of post-partum placental-related complications to naturally conceived pregnancies, unlike IVF-ICSI pregnancies. It is possible that infertility itself is the main mediator for post-partum complications in IVF-ICSI pregnancies.

Opportunities and Limits of Conventional IVF versus ICSI: It Is Time to Come off the Fence

Conventional IVF (c-IVF) is one of the most practiced assisted reproductive technology (ART) approaches used worldwide. However, in the last years, the number of c-IVF procedures has dropped dramatically in favor of intracytoplasmic sperm injection (ICSI) in cases of non-male-related infertility. In this review, we have outlined advantages and disadvantages associated with c-IVF, highlighting the essential steps governing its success, its limitations, the methodology differences among laboratories and the technical progress. In addition, we have debated recent insights into fundamental questions, including indications regarding maternal age, decreased ovarian reserve, endometriosis, autoimmunity, single oocyte retrieval-cases as well as preimplantation genetic testing cycles. The “overuse” of ICSI procedures in several clinical situations of ART has been critically discussed. These insights will provide a framework for a better understanding of opportunities associated with human c-IVF and for best practice guidelines applicability in the reproductive medicine field.

Fertility Counseling in BRCA1/2-Mutated Women with Breast Cancer and Healthy Individuals

Breast cancer is the most commonly diagnosed cancer worldwide and the fifth leading cause of cancer death. In 2020, there were 2.3 million new cases, and 685,000 women died from it. Breast cancer among young women under 40 years of age accounts for 5% to 10% of all cases of this cancer. The greater availability of multi-gene sequence analysis by next-generation sequencing has improved diagnosis and, consequently, the possibility of using appropriate therapeutic approaches in BRCA1/2 gene mutation carriers. Treatment of young breast cancer patients affects their reproductive potential by reducing ovarian reserve. It can lead to reversible or permanent premature menopause, decreased libido, and other symptoms of sex hormone deficiency. This requires that, in addition to oncological treatment, patients are offered genetic counseling, oncofertility, psychological assistance, and sexological counseling. Given the number of BRCA1/2 gene mutation carriers among young breast cancer patients, but also thanks to growing public awareness, among their healthy family members planning offspring, the possibility of benefiting from preimplantation testing and performing cancer-risk-reduction procedures: RRM (risk-reducing mastectomy) and RRSO (risk-reducing salpingo-oophorectomy) significantly increase the chance of a genetically burdened person living a healthy life and giving birth to a child not burdened by the parent's germline mutation. The goal of this paper is to show methods and examples of fertility counselling for BRCA1/2 gene mutation carriers, including both patients already affected by cancer and healthy individuals.

Implementation and Evaluation of Preimplantation Genetic Testing at Vilnius University Hospital Santaros Klinikos

Background and Objectives

The most effective treatment of infertility is in vitro fertilization (IVF). IVF with Preimplantation Genetic Testing (PGT) allows to identify embryos with a genetic abnormality associated with a specific medical disorder and to select the most optimal embryos for the transfer. PGT is divided into structural rearrangement testing (PGT-SR), monogenetic disorder testing (PGT-M), and aneuploidy testing (PGT-A). This study mostly analyzes PGT-SR, also describes a few cases of PGT-M. The aim of this study was to implement PGT procedure at Vilnius University Hospital Santaros Klinikos (VUHSK) Santaros Fertility Centre (SFC) and to perform retrospective analysis of PGT procedures after the implementation.

Materials and Methods

A single-center retrospective analysis was carried out. The study population included infertile couples who underwent PGT at SFC, VUHSK from January 01st, 2017 to December 31st, 2020. Ion PGM platform (Life Technologies, USA) and Ion ReproSeq PGS View Kit (Life Technologies, USA) were used for the whole genome amplification. Results were assessed using descriptive statistics.

Results

PGT was successfully implemented in VUHSK in 2017. During the analyzed time period, thirty-four PGT procedures were performed for 26 couples. Two procedures were performed in 2017, 7 procedures - in 2018, 13 - in 2019, and 12 - in 2020. In comparison with all IVF procedures, 2.5% procedures were IVF with PGT, a highest percentage was in 2020 (3.8% of all procedures). The main indication for PGT was balanced chromosomal rearrangements (in 85.3% cases). In all 34 cases 515 oocytes were aspirated in total, 309 oocytes were fertilized, oocytes fertilization rate exceeded 60%. A normal diploid karyotype was found in 46 (16.8%) biopsied embryos. Out of all PGT procedures, 9 (26.5%) resulted in a clinical pregnancy. Six (66.7%) pregnancies were confirmed in 2019, and 3 (33.3%) - in 2020. Three (33.3%) pregnancies resulted in spontaneous abortion, 6 (66.7%) - in delivery.

Conclusions

The implementation of PGT in VUHSK was successful. The most common indication for PGT was a reciprocal translocation. Oocytes fertilization rate exceeded 60%, a normal karyotype was found less than in one-fifth of biopsied embryos. A highest clinical pregnancy rate was achieved in 2019 when almost half of women conceived, which is probably related to the experience gained by the multidisciplinary team. This is the first study analyzing IVF with PGT in Lithuania, however, the results should be interpreted with caution due to a low number of total procedures performed.

Evaluating standards for 'serious' disease for preimplantation genetic testing: a multi-case study on regulatory frameworks in Japan, the UK, and Western Australia

BACKGROUND

A number of countries are leading the way in creating regulatory frameworks for preimplantation genetic testing (PGT). Among these countries, a point of consensus is that PGT may be used to avoid the birth of a child with a serious genetic disease. However, standards for evaluating disease severity in this context are not always clear. Considering the numerous medical and social implications of defining a standard for serious disease, our study sought out to better understand how disease severity for PGT is being defined by analyzing and comparing the regulatory landscapes for PGT in various countries.

METHODS

We carried out a multi-case study analysis using policy documents from the UK, Western Australia, and Japan. Documentary analysis was used to analyze and compare these documents in terms of medical indications for PGT, evaluation methods of applications for PGT, and review frameworks used during the evaluation process, which includes the specific medical and social factors that are considered.

RESULTS

Within our three case studies, medical indications for PGT are based on an estimated risk of the woman giving birth to a child with a genetic abnormality with known clinical deficits. Evaluation methods for approving applications for PGT include reference to a pre-approved list of genetic conditions (the UK) and case-by-case reviews (all case studies). Review frameworks for case-by-case reviews include reference to a list of considered factors (the UK and Western Australia) and a definition statement of disease severity (Japan), which provide insight into interpretations of disease severity in each context.

CONCLUSIONS

The results of this study point to the possible medical and social impacts of PGT regulatory frameworks on multiple stakeholders. Furthermore, it suggests that impacts in this case are not only caused by whether PGT is permitted or not, but also by the circumstances under which it is allowed and how decisions regarding its approval are made. Our results may serve as valuable insights for countries that already have established policy for PGT but are considering revision, countries that are without policy, and for discussions on related genetic and reproductive technologies.

The preimplantation genetic testing clinical outcomes of biopsy on vitrification-warming embryos: A retrospective study

AIM

The objective of this study was to assess whether PGT conducted with previously untested vitrified embryos affect the clinical outcomes.

METHODS

A total of 49 patients who underwent biopsy on vitrification-warming embryos for PGT were enrolled from January 2016 to January 2019. The cleavage-stage embryos were thawed and cultured into the blastocyst stage for biopsy. During this period, 195 patients underwent routine PGT and FET, whose embryos were biopsied before frozen were used as the control group. The clinical outcomes were further compared between the two groups after a 1:2 PSM.

RESULTS

There were 47 transferable blastocysts in 30 patients, while 19 patients without transferable embryos, who performed biopsy on vitrification-warming embryos for PGT. During this study period, 27 patients have already underwent FET with the clinical pregnancy rate was 66.7% (18/27). After 1:2 PSM, 24 patients in the biopsy on vitrification-warming embryo group and 48 patients in the control group were compared, the clinical pregnancy rate (68.8% vs. 70.8%, p = 0.86), miscarriage rate (18.2% vs. 11.8%, p = 0.86), or live birth rate (52.1% vs. 62.5%, p = 0.40) had no significant difference. And the transferable blastocyst rate or the clinical pregnancy rate in the vitrification-warming cleavage-stage embryo group was not significantly different from those in the vitrification-warming blastocyst group. In addition, the PGT clinical outcomes of biopsy on vitrification-warming embryos had no significant difference between IVF-fertilized embryos and ICSI-fertilized embryos.

CONCLUSION

Biopsy on the vitrification-warming embryos with a dual vitrified cryopreservation does not affect the embryo quality or the PGT clinical outcomes.

Multidisciplinary management for Peutz-Jeghers syndrome and prevention of vertical transmission to offspring using preimplantation genetic testing

BACKGROUND

Peutz Jeghers syndrome (PJS) is an autosomal dominant genetic disorder caused by STK11 mutation with a predisposition to gastrointestinal polyposis and cancer. PJS patients suffer poor quality of life and are highly concerned about whether deleterious mutations transmit to their offspring. Therefore, this study aimed to propose feasible clinical management and provide effective preimplantation genetic testing for monogenic defect (PGT-M) strategies to protect offspring from inheriting the disease.

METHODS

A hospital-based clinical retrospective analysis reviewing the clinical characteristics and fertility aspects was first conducted on 51 PJS patients at the First Affiliated Hospital of Zhengzhou University between January 2016 and March 2021. Among the 51 patients, the PGT-M strategy was further carried out in 4 couples, which started with a biopsy of the trophectoderm cells of embryos and whole genome amplification using multiple displacement amplification. Thereafter, single nucleotide polymorphism linkage analyses based on karyomapping were performed with copy number variations of the embryos identified simultaneously. Finally, prenatal diagnosis was used to verify the validity of the PGT-M results.

RESULTS

A comprehensive management flowchart adopted by the multidisciplinary team model was formulated mainly focusing on clinical genetic and gastrointestinal aspects. Under the guidelines of this management, 32 embryos from 4 PJS pedigrees were diagnosed and 2 couples successfully conceived healthy babies free of the STK11 pathogenic mutation.

CONCLUSIONS

Our comprehensive management could help affected families avoid having children with PJS through preimplantation genetic testing and provide meaningful guidance for multidisciplinary clinical practice on PJS.

Indian Society for Assisted Reproduction Consensus Guidelines on Preimplantation Genetic Testing in In vitro Fertilization Clinics

Study Question

What are the good practice guidelines for Pre implantation genetic testing applicable in INDIA?

What is Already Known

Pre-Implantation Genetic Testing (PGT) is not new in India. It is used to identify euploid embryos for transfer, thus enabling couples to achieve a healthy pregnancy. There has been a lot of controversy surrounding PGT in the international forums; most of these debates have failed to reach a consensus on whether PGT should be offered or its concerns be validated more.

Study Design Size Duration

This is the report of a 2-day consensus meeting where two moderators were assigned to a group of experts to collate information on Pre implantation genetic testing and embryo biopsy practices in INDIA. This meeting utilised surveys, available scientific evidence and personal laboratory experience into various presentations by experts on pre-decided specific topics.

Participants/Materials Setting Methods

Expert professionals from ISAR representing clinical, embryological and genetic fields.

Main Results and the Role of Chance

The report is divided into various components defining the terminologies, the various requirements, qualifications, recommendations on PGT -A,M,SR, and quality management: the report and recommendations of the expert panel reflect the discussion on each of the topics and try to lay down good practice points for labs to follow.

Limitations Reasons for Caution

The recommendations are solely based on expert opinion. Future availability of data may warrant an update of the same.

Wider Implications of the Findings

These guidelines can help labs across the country to standardise their PGT services and improve clinical outcomes.

Study Funding/Competing InterestS

The consensus meeting and writing of the paper was supported by funds from CooperSurgical India.

You can't keep a bad idea down: Dark history, death, and potential rebirth of eugenics

"Be careful what you wish for": This adage guides both how this project came to life, and how the topic covered in this review continues to unfold. What began as talks between two friends on shared interests in military history led to a 4-year discussion about how our science curriculum does little to introduce our students to societal and ethical impacts of the science they are taught. What emerged was a curricular idea centered on how "good intentions" of some were developed and twisted by others to result in disastrous consequences of state-sanctioned eugenics. In this article, we take the reader (as we did our students) through the long and soiled history of eugenic thought, from its genesis to the present. Though our focus is on European and American eugenics, we will show how the interfaces and interactions between science and society have evolved over time but have remained ever constant. Four critical 'case studies' will also be employed here for deep, thoughtful exploration on a particular eugenic issue. The goal of the review, as it is with our course, is not to paint humanity with a single evil brush. Instead, our ambition is to introduce our students/readers to the potential for harm through the misapplication and misappropriation of science and scientific technology, and to provide them with the tools to ask the appropriate questions of their scientists, physicians, and politicians.

Evolution and Utility of Preimplantation Genetic Testing for Monogenic Disorders in Assisted Reproduction - A Narrative Review

Preimplantation genetic testing (PGT) for monogenic disorders and assisted reproductive technology have evolved and progressed in tandem. PGT started with single-cell polymerase chain reaction (PCR) followed by fluorescent in situ hybridisation for a limited number of chromosomes, later called 'preimplantation genetic diagnosis (PGD) version 1'. This review highlights the various molecular genetic techniques that have evolved to detect specific inherited monogenic disorders in the preimplantation embryo. Literature review in English was performed in PubMed from 1990 to 2021, using the term 'preimplantation genetic diagnosis'. With whole-genome amplification, multiple copies of embryonic DNA were created. This helped in avoiding misdiagnosis caused by allele dropout. Multiplex fluorescent PCR analysed informative short tandem repeats (STR) and detected mutations simultaneously on automated capillary electrophoresis sequencers by mini-sequencing. Comparative genomic hybridisation (CGH) and array CGH were used for 24 chromosome aneuploidy screening. Subsequently, aneuploidies were detected by next-generation sequencing using single-nucleotide polymorphism arrays, while STR markers were used for haplotyping. 'PGD version 2' included accurate marker-based diagnosis of most monogenic disorders and detection of aneuploidy of all chromosomes. Human leukocyte antigen matching of embryos has important implications in diagnosis and cure of haemoglobinopathies and immunodeficiencies in children by means of matched related haematopoietic stem cell transplantation from an unaffected 'saviour sibling' obtained by PGT.

Euploid Day-5 Blastocysts Versus Euploid Day-6 Blastocysts — Will the Reproductive Outcomes Differ? An Observational Study

Background and objective: Day-5 blastocyst embryos are usually chosen for assisted reproductive therapy. We compared the reproductive outcomes of the euploid blastocysts developed on Day 5 versus Day 6.

Methods: This single-center, retrospective observational study analyzed patients aged 25–45 years, who underwent intracytoplasmic sperm injection from December 2014 to November 2018. Depending on the day of trophectoderm biopsy, patients were categorized into Day-5 and Day-6 groups. Percentages of euploid embryos were calculated for both groups, and elective single euploid blastocysts were transferred in a frozen embryo transfer (FET) cycles. The study endpoints were the comparisons of the reproductive outcomes including clinical pregnancy rate (CPR), implantation rate (IR), miscarriage rate (MR), and live birth rate (LBR) between Day-5 and Day-6 euploid FET groups.

Results: A total of 801 embryos from 184 patients were evaluated [Day 5 ([Formula: see text]=769); Day 6 ([Formula: see text]=32); 42.45% were euploid] with the rate of euploidy in Day-5 and Day-6 groups at 42.52% and 40.62%, respectively. A total of 126 patients underwent FET with 126 elective single euploid embryos (Day 5: 117; Day 6: 9). For Day-5 versus Day-6 groups, a significantly higher IR (61.54% vs. 44.44%; [Formula: see text] = 0.0531), CPR (61.54% vs. 44.44%; [Formula: see text] = 0.0531), and LBR (61.54% vs. 33.33%; [Formula: see text] = 0.0014) were reported. Multivariate analysis on ANOVA suggested, comparable pregnancy rates at Day 5 and Day 6 ([Formula: see text] = 0.728).

Conclusions: Day-5 euploid blastocysts seem to offer better reproductive outcomes than Day-6 euploid blastocysts. Further research is recommended to evaluate the reproductive outcomes of Day-6 blastocysts.

Specialist physicians' referral behavior regarding preimplantation genetic testing for single-gene disorders: Is there room to grow?

Objective

To assess whether primary care specialists’ demographics, specialty, and knowledge of preimplantation genetic testing for monogenic disorders (PGT-M) influence their practice patterns.

Design

Cross-sectional survey study.

Setting

Academic medical center.

Patient(s)

Not applicable.

Intervention(s)

None.

Main Outcome Measure(s)

Objective PGT-M knowledge, subjective comfort with PGT-related topics, PGT care practices (discussions/referrals), and PGT-M implementation barriers.

Result(s)

Our survey had 145 respondents: 65 obstetrician/gynecologists, 36 internists, and 44 pediatricians. Overall, 88% believed that patients at a risk of passing on genetic disorders should be provided PGT-M information. However, few discussed PGT-M with their patients (24%) or referred them for testing (23%). Over half (63%) believed that the lack of physician knowledge was a barrier to PGT use. In terms of subjective comfort with PGT, only 1 in 5 physicians felt familiar enough with the topic to answer patient questions. There were higher odds of discussing (odds ratio, 3.21; 95% confidence interval, 1.75–5.87) or referring for PGT (odds ratio, 2.52; 95% confidence interval, 1.41–4.51) for each additional 0.5 correct answers to PGT knowledge-related questions. The odds of referring patients for PGT-M were the highest among obstetrician/gynecologists compared with those among the internists and pediatricians.

Conclusion(s)

Physician specialty and PGT knowledge were associated with PGT-M care delivery practices. Although most specialists believed in equipping at-risk patients with PGT-M information, <1 in 4 discussed or referred patients for PGT. The low levels of PGT-related care among providers may be owed to inadequate knowledge of and comfort with the topic. An opportunity to promote greater understanding of PGT-M among primary care specialists exists and can in turn improve the use of referrals to PGT-M services.

The Technological Advances in Embryo Selection and Genetic Testing: A Look Back at the Evolution of Aneuploidy Screening and the Prospects of Non-Invasive PGT

Since the birth of the first IVF baby, Louise Brown, in 1978, researchers and clinicians have sought ways to improve pregnancy outcomes through embryo selection. In the 1990s, blastomere biopsy and fluorescence in situ hybridization (FISH) were developed in human embryos for the assessment of aneuploidy and translocations. Limitations in the number of chromosomes that could be assayed with FISH lead to the development of comparative genomic hybridization (CGH); however, pregnancy rates overall were not improved. The later development of trophectoderm biopsy with comprehensive chromosome screening (CCS) technologies, as well as the subsequent development of next-generation sequencing (NGS), have shown much greater promise in improving pregnancy and live birth rates. Recently, many studies are focusing on the utilization of non-invasive preimplantation genetic testing (niPGT) in an effort to assess embryo ploidy without exposing embryos to additional interventions.

Three models for the regulation of polygenic scores in reproduction

The past few years have brought significant breakthroughs in understanding human genetics. This knowledge has been used to develop 'polygenic scores' (or 'polygenic risk scores') which provide probabilistic information about the development of polygenic conditions such as diabetes or schizophrenia. They are already being used in reproduction to select for embryos at lower risk of developing disease. Currently, the use of polygenic scores for embryo selection is subject to existing regulations concerning embryo testing and selection. Existing regulatory approaches include 'disease-based' models which limit embryo selection to avoiding disease characteristics (employed in various formats in Australia, the UK, Italy, Switzerland and France, among others), and 'laissez-faire' or 'libertarian' models, under which embryo testing and selection remain unregulated (as in the USA). We introduce a novel 'Welfarist Model' which limits embryo selection according to the impact of the predicted trait on well-being. We compare the strengths and weaknesses of each model as a way of regulating polygenic scores. Polygenic scores create the potential for existing embryo selection technologies to be used to select for a wider range of predicted genetically influenced characteristics including continuous traits. Indeed, polygenic scores exist to predict future intelligence, and there have been suggestions that they will be used to make predictions within the normal range in the USA in embryo selection. We examine how these three models would apply to the prediction of non-disease traits such as intelligence. The genetics of intelligence remains controversial both scientifically and ethically. This paper does not attempt to resolve these issues. However, as with many biomedical advances, an effective regulatory regime must be in place as soon as the technology is available. If there is no regulation in place, then the market effectively decides ethical issues.

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 14th 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.

Diagnostic Testing for Patients with Spinal Muscular Atrophy

Diagnostic genetic testing for spinal muscular atrophy is key in establishing early diagnosis for affected individuals. Prenatal carrier testing of parents with subsequent testing of the fetus for homozygous SMN1 gene deletion in those at risk of this autosomal recessive disorder as well as newborn screening can identify the vast majority of affected individuals before the onset of symptoms. Patients presenting symptomatically must be genetically confirmed as soon as possible because targeted treatments are now available that profoundly impact symptoms and improve quality of life.

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.

Autosomal dominant tubulointerstitial kidney disease

Autosomal dominant tubulointerstitial kidney disease (ADTKD) is a recently defined entity that includes rare kidney diseases characterized by tubular damage and interstitial fibrosis in the absence of glomerular lesions, with inescapable progression to end-stage renal disease. These diseases have long been neglected and under-recognized, in part due to confusing and inconsistent terminology. The introduction of a gene-based, unifying terminology led to the identification of an increasing number of cases, with recent data suggesting that ADTKD is one of the more common monogenic kidney diseases after autosomal dominant polycystic kidney disease, accounting for ~5% of monogenic disorders causing chronic kidney disease. ADTKD is caused by mutations in at least five different genes, including UMOD, MUC1, REN, HNF1B and, more rarely, SEC61A1. These genes encode various proteins with renal and extra-renal functions. The mundane clinical characteristics and lack of appreciation of family history often result in a failure to diagnose ADTKD. This Primer highlights the different types of ADTKD and discusses the distinct genetic and clinical features as well as the underlying mechanisms.