ESHRE PGD consortium best practice guidelines for amplification-based PGD

Using preimplantation genetic testing for monogenic disease for preventing citrullinemia type 1 transmission

Aim

The aim of this study is to investigate if Preimplantation Genetic Testing (PGT) can effectively identify unreported variants according to American College of Medical Genetics and Genomics (ACMG)to prevent citrullinemia type 1 affection.

Design

This study involves a detailed case analysis of a family with history of citrullinemia type 1, focusing on the use of PGT for monogenic diseases (PGT-M). The genetic variants were identified using ACMG guidelines, and PGT was employed to prevent the inheritance of these variants. The study included haplotype analysis and Sanger sequencing to confirm the results.

Results

The study identified previously unreported variations in the ASS1 gene causing citrullinemia type 1. PGT successfully prevented the transmission of these variants, resulting in the birth of a healthy fetus. However, challenges such as allele dropout (ADO) and gene recombination were encountered during haplotype analysis, which could potentially defeat the diagnosis. The study demonstrated that combining haplotype analysis with Sanger sequencing can enhance the accuracy of PGT.

Conclusion

Preimplantation Genetic Testing (PGT) targeting likely pathogenic and pathogenic variants in the ASS1 gene, as rated by ACMG, allows the birth of healthy infants free from citrullinemia type 1. Additionally, the establishment of single haplotypes and Sanger sequencing can reduce the misdiagnosis rate caused by allele dropout (ADO) and genetic recombination.

Preimplantation Genetic Testing of Spinocerebellar Ataxia Type 3/Machado-Joseph Disease-Robust Tools for Direct and Indirect Detection of the ATXN3 (CAG)n Repeat Expansion

Spinocerebellar ataxia type 3/Machado-Joseph disease (SCA3/MJD) is a neurodegenerative disorder caused by the ATXN3 CAG repeat expansion. Preimplantation genetic testing for monogenic disorders (PGT-M) of SCA3/MJD should include reliable repeat expansion detection coupled with high-risk allele determination using informative linked markers. One couple underwent SCA3/MJD PGT-M combining ATXN3 (CAG)n triplet-primed PCR (TP-PCR) with customized linkage-based risk allele genotyping on whole-genome-amplified trophectoderm cells. Microsatellites closely linked to ATXN3 were identified and 16 markers were genotyped on 187 anonymous DNAs to verify their polymorphic information content. In the SCA3/MJD PGT-M case, the ATXN3 (CAG)n TP-PCR and linked marker analysis results concurred completely. Among the three unaffected embryos, a single embryo was transferred and successfully resulted in an unaffected live birth. A total of 139 microsatellites within 1 Mb upstream and downstream of the ATXN3 CAG repeat were identified and 8 polymorphic markers from each side were successfully co-amplified in a single-tube reaction. A PGT-M assay involving ATXN3 (CAG)n TP-PCR and linkage-based risk allele identification has been developed for SCA3/MJD. A hexadecaplex panel of highly polymorphic microsatellites tightly linked to ATXN3 has been developed for the rapid identification of informative markers in at-risk couples for use in the PGT-M of SCA3/MJD.

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

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

Preimplantation Genetic Testing for Genetic Diseases: Limits and Review of Current Literature

Preimplantation genetic testing (PGT) has emerged as a revolutionary technique in the field of reproductive medicine, allowing for the selection and transfer of healthy embryos, thus reducing the risk of transmitting genetic diseases. However, despite remarkable advancements, the implementation of PGT faces a series of limitations and challenges that require careful consideration. This review aims to foster a comprehensive reflection on the constraints of preimplantation genetic diagnosis, encouraging a broader discussion about its utility and implications. The objective is to inform and guide medical professionals, patients, and society overall in the conscious and responsible adoption of this innovative technology, taking into account its potential benefits and the ethical and practical challenges that it presents.

Robust preimplantation genetic testing of the common F8 Inv22 pathogenic variant of severe hemophilia A using a highly polymorphic multi-marker panel encompassing the paracentric inversion

BACKGROUND

Hemophilia A (HEMA) is an X-linked bleeding disorder caused by reduced/absent coagulation factor VIII expression, as a result of pathogenic variants in the F8 gene. Preimplantation prevention of HEMA should ideally include direct pathogenic F8 variant detection, complemented by linkage analysis of flanking markers to identify the high-risk F8 allele. Linkage analysis is particularly indispensable when the pathogenic variant cannot be detected directly or identified. This study evaluated the suitability of a panel of F8 intragenic and extragenic short tandem repeat markers for standalone linkage-based preimplantation genetic testing for monogenic disorder (PGT-M) of the Inv22 pathogenic variant, an almost 600 kb paracentric inversion responsible for almost half of all severe HEMA globally, for which direct detection is challenging.

METHODS

Thirteen markers spanning 1 Mb and encompassing both F8 and the Inv22 inversion interval were genotyped in 153 unrelated females of Viet Kinh ethnicity.

RESULTS

All individuals were heterozygous for ≥ 1 marker, ~ 90% were heterozygous for ≥ 1 of the five F8 intragenic markers, and almost 98% were heterozygous for ≥ 1 upstream (telomeric) and ≥ 1 downstream (centromeric) markers. A prospective PGT-M couple at risk of transmitting F8 Inv22 were fully informative at four marker loci (2 intra-inversion, 1 centromeric, 1 telomeric) and partially informative at another five (2 intra-inversion, 3 centromeric), allowing robust phasing of low- and high-risk haplotypes. In vitro fertilization produced three embryos, all of which clearly inherited the low-risk maternal allele, enabling reliable unaffected diagnoses. A single embryo transfer produced a clinical pregnancy, which was confirmed as unaffected by amniocentesis and long-range PCR, and a healthy baby girl was delivered at term.

CONCLUSION

Robust and reliable PGT-M of HEMA, including the common F8 Inv22 pathogenic variant, can be achieved with sufficient informative intragenic and flanking markers.

Establishment of linkage phase, using Oxford Nanopore Technologies, for preimplantation genetic testing of Coffin-Lowry syndrome with a de novo RPS6KA3 mutation

Background: This study aimed to perform preimplantation genetic testing (PGT) for a female Coffin-Lowry Syndrome (CLS) patient with a de novo mutation (DNM) in RPS6KA3. It was challenging to establish the haplotype in this family because of the lack of information from affected family members. Hence, we explored a new and reliable strategy for the detection of the DNM in PGT, using Oxford Nanopore Technologies (ONT) and the MARSALA platform. Methods: We performed whole-exome sequencing (WES) on the proband and confirmed the pathogenic mutation by Sanger sequencing. The proband then underwent PGT to prevent the transmission of the pathogenic mutation to her offspring. We diverged from the conventional methods and used long-read sequencing (LRS) on the ONT platform to directly detect the mutation and nearby SNPs, for construction of the haplotype in the preclinical phase of PGT. In the clinical phase of embryo diagnosis, the MARSALA method was used to detect both the SNP-based haplotype and chromosome copy number variations (CNVs), in each blastocyst. Finally, a normal embryo was selected by comparison to the haplotype of the proband and transferred into the uterus. Sanger sequencing and karyotyping were performed by amniocentesis, at 17 weeks of gestation, to confirm the accuracy of PGT. Results: Using WES, we found the novel, heterozygous, pathogenic c.1496delG (p.Gly499Valfs*25) mutation of RPS6KA3 in the proband. The SNP-based haplotype that was linked to the pathogenic mutation site was successfully established in the proband, without the need for other family members to be tested with ONT. Eight blastocysts were biopsied to perform PGT and were assessed with a haplotype linkage analysis (30 SNP sites selected), to give results that were consistent with direct mutation detection using Sanger sequencing. The results of PGT showed that three of the eight blastocysts were normal, without the DNM. Moreover, the patient had a successful pregnancy, after transfer of a normal blastocyst into the uterus, and delivered a healthy baby. Conclusion: The ONT platform, combined with the MARSALA method, can be used to perform PGT for DNM patients without the need for other samples as a reference.

Conventional outcome reporting per IVF cycle/embryo transfer may systematically underestimate chances of success for women undergoing ART: relevant biases in registries, epidemiological studies, and guidelines

Pre-conception counselling and management of expectations about chance of success of IVF/ICSI treatments is an integral part of fertility care. Registry data are usually used to inform patients about expected success rates of IVF/ICSI treatment, as these data should best represent real-world populations and clinical practice. In registries, the success rate of IVF/ICSI treatments is conventionally reported per treatment cycle or per embryo transfer and estimated from data for which several treatment attempts per subject have been pooled (e.g. repetitive IVF/ICSI attempts or repetitive attempts of cryotransfer). This, however, may underestimate the true mean chance of success per treatment attempt, because treatment attempts of women with a poor prognosis will usually be over-represented in a pool of treatment cycle data compared to treatment events of women with a good prognosis. Of note, this phenomenon is also a source of potential bias when comparing outcomes between fresh transfers and cryotransfers, since women can undergo a maximum of only one fresh transfer after each IVF/ICSI treatment, but potentially several cryotransfers. Herein, we use a trial dataset from 619 women, who underwent one cycle of ovarian stimulation and ICSI, a Day 5 fresh transfer and/or subsequent cryotransfers (follow-up of all cryotransfers up to 1 year after the start of stimulation), to exemplify the underestimation of the live birth rate, when not accounting for repeated transfers in the same woman. Using mixed-effect logistic regression modelling, we show that the mean live birth rate per transfer per woman in cryocycles is underestimated by the factor 0.69 (e.g. live birth rate per cryotransfer of 36% after adjustment versus 25% unadjusted). We conclude that the average chance of success of treatment cycles of women of a given age, treated in a given centre, etc., when conventionally calculated per cycle or per embryo transfer from a pool of treatment events, do not apply to an individual woman. We suggest that patients are, especially at the outset of treatment, systematically confronted with mean estimates of success per attempt that are too low. Live birth rates per transfer from datasets encompassing multiple transfers from single individuals could be more accurately reported using statistical models accounting for the correlation between cycle outcomes within women.

Preimplantation genetic testing and child health: a national register-based study

STUDY QUESTION

Is preimplantation genetic testing (PGT) associated with adverse perinatal outcome and early childhood health?

SUMMARY ANSWER

Children born after PGT had comparable perinatal outcomes to children born after IVF/ICSI and comparable findings regarding early childhood health.

WHAT IS KNOWN ALREADY

PGT is offered to couples affected by monogenic disorders (PGT-M) or inherited chromosomal aberrations (PGT-SR), limiting the risk of transferring the disorder to the offspring. PGT, an invasive technique, requires genetic analysis of one or up to ten cells from the embryo and is combined with IVF or ICSI. Several studies, most of them small, have shown comparable results after PGT and IVF/ICSI concerning perinatal outcome. Only a few studies with limited samples have been published on PGT and childhood health.

STUDY DESIGN, SIZE, DURATION

We performed a register-based study including all singletons born after PGT (n = 390) in Sweden during 1 January 1996-30 September 2019. Singletons born after PGT were compared with all singletons born after IVF/ICSI (n = 61 060) born during the same period of time and with a matched sample of singletons (n = 42 034) born after spontaneous conception selected from the Medical Birth Register. Perinatal outcomes, early childhood health, and maternal outcomes were compared between pregnancies after PGT and IVF/ICSI as well as between pregnancies after PGT and spontaneous conception. Primary outcomes were preterm birth (PTB) and low birthweight (LBW) whereas childhood morbidity was the secondary outcome.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Data on women who went through PGT and gave birth were obtained from the local databases at the two PGT centres in Sweden, whereas data on IVF treatment for the IVF/ICSI group were obtained from the national IVF registers. These data were then cross-linked to national health registers; the Medical Birth Register, the Patient Register, and the Cause of Death Register. Logistic multivariable regression analysis and Cox proportional hazards models were performed with adjustment for relevant confounders.

MAIN RESULTS AND THE ROLE OF CHANCE

The mean follow-up time was 4.6 years for children born after PGT and 5.1 years for children born after spontaneous conception, whereas the mean follow-up time was 9.0 years for children born after IVF/ICSI. For perinatal outcomes, PTB occurred in 7.7% of children after PGT and in 7.3% of children after IVF/ICSI, whereas the rates were 4.9% and 5.2% for LBW (adjusted odds ratio (AOR) 1.22, 95% CI 0.82-1.81 and AOR 1.17, 95% CI 0.71-1.91, respectively). No differences were observed for birth defects. In comparison to spontaneous conception, children born after PGT had a higher risk for PTB (AOR 1.73, 95% CI 1.17-2.58). Regarding early childhood health, the absolute risk of asthma was 38/390 (9.7%) in children born after PGT and 6980/61 060 (11.4%) in children born after in IVF/ICSI, whereas the corresponding numbers were 34/390 (8.7%) and 7505/61 060 (12.3%) for allergic disorders. Following Cox proportional hazards models, no significant differences were found for these outcomes. Sepsis, hypothyroidism, attention deficit hyperactivity disorder, autism spectrum disorders, mental retardation, cerebral palsy, and epilepsy were diagnosed in a maximum of three PGT children. No PGT children died during the follow-up period. Regarding maternal outcomes, the rates of placenta praevia and caesarean delivery were significantly higher after PGT in comparison to spontaneous conception (AOR 6.46, 95% CI 3.38-12.37 and AOR 1.52, 95% CI 1.20-1.92, respectively), whereas no differences were seen comparing pregnancies after PGT and IVF/ICSI.

LIMITATIONS, REASONS FOR CAUTION

The rather small sample size of children born after PGT made it impossible to adjust for all relevant confounders including fertilization method and culture duration. Moreover, the follow-up time was short for most of the children especially in the PGT group, probably lowering the absolute number of diagnoses in early childhood.

WIDER IMPLICATIONS OF THE FINDINGS

The results are reassuring and indicate that the embryo biopsy itself has no adverse effect on the perinatal, early childhood, or maternal outcomes. Although the results are comparable to IVF/ICSI also regarding early childhood outcome, they should be taken with caution due to the low number of children with diagnoses and short follow-up time. Long-term follow-up studies on children born after PGT are scarce and should be conducted considering the invasiveness of the technique.

STUDY FUNDING/COMPETING INTEREST(S)

The study was financed by grants from the Swedish state under the agreement between the Swedish government and the county councils, the ALF-agreement (LUA/ALF 70940), the Board of National Specialised Medical Care at Sahlgrenska University Hospital and Hjalmar Svensson Research Foundation. There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Combined Preimplantation Genetic Testing for Genetic Kidney Disease: Genetic Risk Identification, Assisted Reproductive Cycle, and Pregnancy Outcome Analysis

Background

Genetic kidney disease is a major cause of morbidity and mortality in neonates and end-stage renal disease (ESRD) in children and adolescents. Genetic diagnosis provides key information for early identification of congenital kidney disease and reproductive risk counseling. Preimplantation genetic testing for monogenic disease (PGT-M) as a reproductive technology helps prospective parents to prevent passing on disease-causing mutations to their offspring.

Materials and Methods

A retrospective cohort of couples counseled on PGT who had a risk to given birth to a child with genetic kidney disease or had a history of prenatal fetal kidney and urinary system development abnormalities from 2011 to 2021. Through a combination of simultaneously screening for aneuploidy and monogenic kidney disease, we achieved reproductive genetic intervention.

Results

A total of 64 couples counseled on PGT for monogenic kidney disease in a single reproductive center during the past 10 years, of whom 38 different genetic kidney diseases were identified. The most frequent indications for referral were autosomal recessive disease (54.7%), then autosomal dominant disease (29.7%), and X-linked disease (15.6%). Polycystic kidney disease was the most common diseases counted for 34.4%. After oocyte-retrieval in all of 64 females, a total of 339 embryos were diagnosed and 63 embryos were transferred in succession. Among 61 cycles of frozen-embryo transfer (FET), ongoing pregnancy/live birth rate (OP/LBR) reached 57.38%. The cumulative OP/LBR in our cohort for the 64 couples was 54.69%. In addition, we have carried out expanded carrier screening (ECS) in all the in vitro fertilization (IVF) couples performed PGT covering 7,311 individuals. The carrier frequency of the candidate genes for monogenic kidney diseases accounted for 12.19%.

Conclusion

Overall, the customization PGT-M plan in our IVF center is pivotal to decreasing the morbidity and implementing reproductive genetic intervention of genetic kidney disease.

Using affected embryos to establish linkage phase in preimplantation genetic testing for thalassemia

BACKGROUND

This study aimed to evaluate the ability of next-generation sequencing (NGS) to conduct preimplantation genetic testing (PGT) for thalassemia using affected embryos.

METHODS

This study included data from 36 couples who underwent PGT for thalassemia without probands and relative pedigrees. NGS results were compared with prenatal diagnosis results.

RESULTS

Thirty-six couples (29 α-thalassemia and 7 β-thalassemia) underwent 41 PGT cycles (31 α-thalassemia and 10 β-thalassemia). Analysis using NGS produced conclusive results for all biopsied blastocysts (100%, 217/217). One hundred and sixty (73.7%, 160/217) were unaffected by thalassemia. Preimplantation genetic testing for aneuploidy revealed that 112 (70.0%, 112/160) were euploid. Single blastocysts were transferred into the uteri of 34 women (53 frozen embryo transfer [FET] cycles). Thirty-two cycles resulted in clinical pregnancies, with a clinical pregnancy rate of 60.1% (32/53) per FET cycle. Twenty-two cycles (22 couples) resulted in 23 live births, with a live birth rate of 43.4% (23/53; 3 cycles were ongoing pregnancies). All 25 embryos' prenatal diagnosis results and/or thalassemia gene analyses after delivery were concordant with the NGS-PGT results. Seven embryos (21.9%, 7/32) were miscarried before 12 weeks' gestation, and the abortion villus in four showed a normal karyotype and thalassemia results consistent with the NGS-PGT results. Aborted fetus samples from 3 cycles were not available because the pregnancy lasted less than 5 weeks.

CONCLUSION

NGS can be used to conduct PGT for thalassemia using affected embryos as a reference.

TRIAL REGISTRATION

Retrospectively registered.

Evaluating the application value of NGS-based PGT-A by screening cryopreserved MDA products of embryos from PGT-M cycles with known transfer outcomes

PURPOSE

To determine the application value of next-generation sequencing (NGS)-based preimplantation genetic testing for aneuploidies (PGT-A).

METHODS

We conducted a retrospective case-control study on a cohort of frozen-thawed embryo transfer (FET) cycles following preimplantation genetic testing for monogenic disorders (PGT-M) between 2014 and 2017. Cycles that produced live births or early miscarriages were divided into live birth group (n = 76) or miscarriage group (n = 19), respectively. The NGS-based aneuploidy screening was performed on the multiple displacement amplification (MDA) products of the embryonic trophectoderm biopsy samples that were cryopreserved following PGT-M.

RESULTS

In the live birth group, 75% (57/76) embryos were euploid and 14.5% (11/76) were aneuploid. The remaining 10.5% (8/76) embryos were NGS-classified mosaic with the high- (≥ 50%) and low-level (< 50%) mosaicism rates at 7.9% (6/76) and 2.6% (2/76), respectively. In the miscarriage group, only 23.5% (4/17) embryos were aneuploid, while 58.8% (10/17) were euploid and 17.6% (3/17) were NGS-classified mosaic with the high- and low-level mosaicism rates at 11.8% (2/17) and 5.9% (1/17), respectively. For live birth and miscarriage groups, the transferable rate was 82.9% (63/76) and 70.6% (12/17), respectively, whereas the untransferable rate was 17.1% (13/76) and 29.4% (5/17), respectively.

CONCLUSION

The application of NGS-based PGT-A remains questionable, as it may cause at least one in six embryos with reproductive potential to be discarded and prevent miscarriage in less than one in three embryos in single-gene disease carriers.

Preimplantation Genetic Diagnosis in Hereditary Hearing Impairment

Sensorineural hearing impairment is a common sensory deficit in children and more than 50% of these cases are caused by genetic etiologies, that is, hereditary hearing impairment (HHI). Recent advances in genomic medicine have revolutionized the diagnostics of, and counseling for, HHI, including preimplantation genetic diagnosis (PGD), thus providing parents-to-be with better reproductive choices. Over the past decade, we have performed PGD using the amplification refractory mutation system quantitative polymerase chain reaction (ARMS-qPCR) technique in 11 couples with a history of HHI, namely eight with GJB2 variants, one with OTOF variants, one with SLC26A4 variants, and one with an MITF variant. We demonstrated that PGD can be successfully applied to HHI of different inheritance modes, namely autosomal dominant or recessive, and phenotypes, namely syndromic or non-syndromic HHI. However, certain ethical concerns warrant scrutiny before PGD can be widely applied to at-risk couples with a history of HHI.

Preimplantation Genetic Diagnosis for DEB by Detecting a Novel Family-Specific COL7A1 Mutation in Vietnam

Background

Epidermolysis bullosa (EB) is a disorder characterized by the appearance of blisters, erosions and wounds in response to minimal trauma. The disease manifests with noticeable symptoms ranging from mild to severe, classified into four major types: epidermolysis bullosa simplex (EBS), junctional epidermolysis bullosa (JEB), dystrophic epidermolysis bullosa (DEB) and Kindler syndrome. Preimplantation genetic diagnosis for the disease remains the only available option for families at risk for the recurrence of the disorder without having to terminate an ongoing pregnancy.

Materials and Methods

A novel COL7A1 mutation was used to design primers for the polymerase chain reaction (PCR) to amplify the segment spanning the mutation in the family and their in-vitro fertilization (IVF) embryos. Then, the PCR products were sequenced with Sanger sequencing to detect the alteration in the allele, and some embryos would go through NGS-based preimplantation screening for chromosomal abnormalities.

Results

The established protocol for EB detected mutant allele in 6/9 embryos (66.6%), while the remaining 3 embryos (33.4%) appeared to not carry any mutation. Only one among 3 embryos was recommended to be transferred into the mother's uterus.

Conclusion

The established preimplantation genetic diagnosis procedure is helpful to families affected by epidermolysis bullosa caused by COL7A1 mutations but wish to have healthy children.

Obstetric and neonatal outcomes of pregnancies resulting from preimplantation genetic testing: a systematic review and meta-analysis

BACKGROUND

Preimplantation genetic testing (PGT) includes methods that allow embryos to be tested for severe inherited diseases or chromosomal abnormalities. In addition to IVF/ICSI and repeated freezing and thawing of the embryos, PGT requires a biopsy to obtain embryonic genetic material for analysis. However, the potential effects of PGT on obstetric and neonatal outcomes are currently uncertain.

OBJECTIVE AND RATIONALE

This study aimed to investigate whether pregnancies conceived after PGT were associated with a higher risk of adverse obstetric and neonatal outcomes compared with spontaneously conceived (SC) pregnancies or pregnancies conceived after IVF/ICSI.

SEARCH METHODS

PubMed, EMBASE, MEDLINE, Web of Science and The Cochrane Library entries from January 1990 to January 2021 were searched. The primary outcomes in this study were low birth weight (LBW) and congenital malformations (CMs), and the secondary outcomes included gestational age, preterm delivery (PTD), very preterm delivery (VPTD), birth weight (BW), very low birth weight (VLBW), neonatal intensive care unit (NICU) admission, hypertensive disorders of pregnancy (HDP), gestational diabetes, placenta previa and preterm premature rupture of membranes (PROM). We further pooled the results of PGT singleton pregnancies. Subgroup analyses included preimplantation genetic diagnosis (PGD), preimplantation genetic screening (PGS), cleavage-stage biopsy combined with fresh embryo transfer (CB-ET) and blastocyst biopsy combined with frozen-thawed embryo transfer (BB-FET).

OUTCOMES

This meta-analysis included 15 studies involving 3682 babies born from PGT pregnancies, 127 719 babies born from IVF/ICSI pregnancies and 915 222 babies born from SC pregnancies. The relative risk (RR) of LBW was higher in PGT pregnancies compared with SC pregnancies (RR = 3.95, 95% confidence interval [CI]: 2.32-6.72), but the risk of CMs was not different between the two groups. The pooled results for the risks of LBW and CMs were similar in PGT and IVF/ICSI pregnancies. The risks of PTD (RR = 3.12, 95% CI: 2.67-3.64) and HDP (RR = 3.12, 95% CI: 2.18-4.47) were significantly higher in PGT pregnancies compared with SC pregnancies. Lower gestational age (mean difference [MD] = -0.76 weeks, 95% CI -1.17 to -0.34) and BW (MD = -163.80 g, 95% CI: -299.35 to -28.24) were also noted for PGT pregnancies compared with SC pregnancies. Nevertheless, compared with IVF/ICSI pregnancies, the risks of VPTD and VLBW in PGT pregnancies were significantly decreased by 41% and 30%, respectively, although the risk of HDP was still significantly increased by 50% in PGT pregnancies compared with IVF/ICSI pregnancies. The combined results of obstetric and neonatal outcomes of PGT and IVF/ICSI singleton pregnancies were consistent with the overall results. Further subgroup analyses indicated that both PGD and PGS pregnancies were associated with a higher risk of PTD and a lower gestational age compared with SC pregnancies.

WIDER IMPLICATIONS

This meta-analysis showed that PGT pregnancies may be associated with increased risks of LBW, PTD and HDP compared with SC pregnancies. The overall obstetric and neonatal outcomes of PGT pregnancies are favourable compared with those of IVF/ICSI pregnancies, although PGT pregnancies were associated with a higher risk of HDP. However, because the number of studies that could be included was limited, more randomised controlled trials and prospective cohort studies are needed to confirm these conclusions.

Prenatal diagnostic techniques and IVF in patients with coagulopathies

Hemophilia and other hereditary coagulopathies tend to be associated with a huge negative impact both for individuals who suffer the disease and for their families. In this respect, hemophilia carriers feel the need to make reproductive decisions which will inevitably affect their children, their families and from themselves. Genetic and reproductive counseling is of the essence to alleviate these women's distress. Prenatal diagnosis and preimplantation genetic diagnosis (PGD) allow couples at high-risk of transmitting genetic diseases like hemophilia and other hereditary coagulopathies to prevent the birth of children with the disease. The main difference between prenatal diagnosis and PGD is related to the time at which diagnosis is made. Prenatal diagnosis is done when the woman is pregnant, and both the performance of the technique and its result can affect the course of pregnancy. PGD is a diagnostic procedure in which embryos created in vitro are analyzed for genetic defects before being transferred to the uterus. Performance of both prenatal diagnosis and PGD is subject to a few prerequisites: the establishment of an exact clinical diagnosis, an understanding of the parental genetic alterations that are responsible for the disease and technical feasibility of genetic diagnosis. These couples should be provided with complete, up-to-date and easy-to-understand information.

Next-generation sequence-based preimplantation genetic testing for monogenic disease resulting from maternal mosaicism

BACKGROUND

Mosaicism poses challenges for genetic counseling and preimplantation genetic testing for monogenic disorders (PGT-M). NGS-based PGT-M has been extensively used to prevent the transmission of monogenic defects, but it has not been evaluated in the application of PGT-M resulting from mosaicism.

METHODS

Four women suspected of mosaicism were confirmed by ultra-deep sequencing. Blastocyst trophectoderm cells and polar bodies were collected for whole genome amplification, followed by pathogenic variants detection and haplotype analysis based on NGS. The embryos free of the monogenic disorders were transplantable.

RESULTS

Ultra-deep sequencing confirmed that the four women harbored somatic mosaic variants, with the proportion of variant cells at 1.12%, 9.0%, 27.60%, and 91.03%, respectively. A total of 25 blastocysts were biopsied and detected during four PGT cycles and 5 polar bodies were involved in one cycle additionally. For each couple, a wild-type embryo was successfully transplanted and confirmed by prenatal diagnosis, resulting in the birth of four healthy infants.

CONCLUSIONS

Mosaic variants could be effectively evaluated via ultra-deep sequencing, and could be prevented the transmission by PGT. Our work suggested that an NGS-based PGT approach, involving pathogenic variants detection combined with haplotype analysis, is crucial for accurate PGT-M with mosaicism.

Identity-by-state-based haplotyping expands the application of comprehensive preimplantation genetic testing

STUDY QUESTION

Is it possible to haplotype parents using parental siblings to leverage preimplantation genetic testing (PGT) for monogenic diseases and aneuploidy (comprehensive PGT) by genome-wide haplotyping?

SUMMARY ANSWER

We imputed identity-by-state (IBS) sharing of parental siblings to phase parental genotypes.

WHAT IS KNOWN ALREADY

Genome-wide haplotyping of preimplantation embryos is being implemented as a generic approach for genetic diagnosis of inherited single-gene disorders. To enable the phasing of genotypes into haplotypes, genotyping the direct family members of the prospective parent carrying the mutation is required. Current approaches require genotypes of either (i) both or one of the parents of the affected prospective parent or (ii) an affected or an unaffected child of the couple. However, this approach cannot be used when parents or children are not attainable, prompting an investigation into alternative phasing options.

STUDY DESIGN, SIZE, DURATION

This is a retrospective validation study, which applied IBS-based phasing of parental haplotypes in 56 embryos derived from 12 PGT families. Genome-wide haplotypes and copy number profiles generated for each embryo using the new phasing approach were compared with the reference PGT method to evaluate the diagnostic concordance.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study included 12 couples with a known hereditary genetic disorder, participating in the comprehensive PGT program and with at least one parental sibling available (e.g. brother and/or sister). Genotyping data from both prospective parents and the parental sibling(s) were used to perform IBS-based phasing and to trace the disease-associated alleles. The outcome of the IBS-based PGT was compared with the results of the clinically implemented reference haplotyping-based PGT method.

MAIN RESULTS AND THE ROLE OF CHANCE

IBS-based haplotyping was performed for 12 PGT families. In accordance with the theoretical prediction of allele sharing between sibling pairs, 6 out of 12 (50%) couples or 23 out of 56 embryos could be phased using parental siblings. In families where phasing was possible, haplotype calling in the locus of interest was 100% concordant between the reference PGT method and IBS-based approach using parental siblings.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Phasing of parental haplotypes will only be possible when the disease locus lies in an informative region (categorized as IBS1). Phasing prospective parents using relatives with reduced genetic relatedness as a reference (e.g. siblings) decreases the size and the occurrence of informative IBS1 regions, necessary for haplotype calling. By including more than one extended family member, the chance of obtaining IBS1 coverage in the interrogated locus can be increased. A pre-PGT work-up can define whether the carrier couple could benefit from this approach.

WIDER IMPLICATIONS OF THE FINDINGS

Phasing by relatives extends the potential of comprehensive PGT, since it allows the inclusion of couples who do not have access to the standard phasing references, such as parents or offspring.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by the KU Leuven grant (C14/18/092), Research Foundation Flanders (FWO; GA09311N), Horizon 2020 innovation programme (WIDENLIFE, 692065) and Agilent Technologies. J.R.V., T.V. and M.Z.E. are co-inventors of a patent ZL910050-PCT/EP2011/060211-WO/2011/157846 'Methods for haplotyping single-cells' and ZL913096-PCT/EP2014/068315-WO/2015/028576 'Haplotyping and copy number typing using polymorphic variant allelic frequencies' licensed to Agilent Technologies. The other authors have no conflict of interest to declare.

Novel variants of the PCCB gene in Chinese patients with propionic acidemia

BACKGROUND AND AIMS

Propionic acidemia (PA) is an autosomal recessive metabolic disorder caused by a deficiency of propionyl-CoA carboxylase and mutations in the PCCA and PCCB genes. In this study, we investigated the clinical characteristics of individuals with PA and conducted genetic analyses to provide new genetic evidence for the diagnosis of PA.

MATERIALS AND METHODS

We conducted whole-exome sequencing and Sanger sequencing in four individuals with PA from three unrelated Chinese families. We also performed a structural analysis of the PCCB protein variants. Couples from the three families included in our study underwent in vitro fertilization with preimplantation genetic testing.

RESULTS

We found five variants of PCCB. These biallelic variants were inherited from heterozygous parental carriers and were located in the functional domain, absent in human population genome datasets, and predicted to be deleterious. These findings indicate that the variants might be responsible for the clinical features observed in these particular patients with PA. Through successful embryo transfer and implantation, one of the couples fortunately gave birth to a healthy child.

CONCLUSION

Overall, our study can expand the mutation spectrum of PCCB and provide useful information for the prenatal diagnosis of PA and genetic counseling for affected individuals.

[Pre-implantation genetic testing: Comparison between cleavage stage and blastocyst biopsy]

OBJECTIVES

Preimplantation genetic testing (PGT) refers to the set of techniques for testing whether embryos obtained through in vitro fertilization have genetic defect. There is a lack of global standardization regarding practices between countries or even from one center to another. In ours, biopsies are preferably performed on day 3 embryos, but also at the blastocyst stage on day 5. The blastocyst biopsy often requires systematic freezing of the embryos before obtaining the genetic results, whereas day 3 biopsy allows fresh embryo transfer of the healthy or balanced embryo after getting the genetic results. We wanted to compare the chances of success for couples performing PGT in our center according to the day of the biopsy.

METHODS

For this, we carried out a retrospective monocentric study including all PGT cycles performed between 2016 and 2019 divided into two groups: day 3 or day 5 biopsy.

RESULTS

There was no significant difference in terms of live birth rate (P=0.7375) after fresh embryo transfers, as well for pregnancy rates, clinical pregnancy rates, implantation rates and miscarriage rates. On the other hand, we observed higher live birth rates after frozen-thawed embryo transfer when the biopsy was performed on day 5 rather on day 3 (P=0.0001). We also wanted to assess what was the most efficient biopsy strategy in our laboratory. Our rates of useful embryos were similar regardless of the day of the biopsy (34% in D3 and 37.7% in D5, P=0.244). No statistical difference was found in the number of unnecessarily biopsied embryos in the two groups. But still, the percentage of embryos biopsied on D5 and immediately frozen was 42.8% (118 blastocysts), while no embryo biopsied on D3 led to this case.

CONCLUSION

Therefore, our results are in favor of generalization of the D5 biopsy as the international standard. However, the organizational, financial and logistical implications that this technic would impose make it unsystematic in our center.

Preimplantation genetic testing for aneuploidies (abnormal number of chromosomes) in in vitro fertilisation

BACKGROUND

In in vitro fertilisation (IVF) with or without intracytoplasmic sperm injection (ICSI), selection of the most competent embryo(s) for transfer is based on morphological criteria. However, many women do not achieve a pregnancy even after 'good quality' embryo transfer. One of the presumed causes is that such morphologically normal embryos have an abnormal number of chromosomes (aneuploidies). Preimplantation genetic testing for aneuploidies (PGT-A), formerly known as preimplantation genetic screening (PGS), was therefore developed as an alternative method to select embryos for transfer in IVF. In PGT-A, the polar body or one or a few cells of the embryo are obtained by biopsy and tested. Only polar bodies and embryos that show a normal number of chromosomes are transferred. The first generation of PGT-A, using cleavage-stage biopsy and fluorescence in situ hybridisation (FISH) for the genetic analysis, was demonstrated to be ineffective in improving live birth rates. Since then, new PGT-A methodologies have been developed that perform the biopsy procedure at other stages of development and use different methods for genetic analysis. Whether or not PGT-A improves IVF outcomes and is beneficial to patients has remained controversial.

OBJECTIVES

To evaluate the effectiveness and safety of PGT-A in women undergoing an IVF treatment.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility (CGF) Group Trials Register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, and two trials registers in September 2019 and checked the references of appropriate papers.

SELECTION CRITERIA

All randomised controlled trials (RCTs) reporting data on clinical outcomes in participants undergoing IVF with PGT-A versus IVF without PGT-A were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, assessed risk of bias, and extracted study data. The primary outcome was the cumulative live birth rate (cLBR). Secondary outcomes were live birth rate (LBR) after the first embryo transfer, miscarriage rate, ongoing pregnancy rate, clinical pregnancy rate, multiple pregnancy rate, proportion of women reaching an embryo transfer, and mean number of embryos per transfer.

MAIN RESULTS

We included 13 trials involving 2794 women. The quality of the evidence ranged from low to moderate. The main limitations were imprecision, inconsistency, and risk of publication bias. IVF with PGT-A versus IVF without PGT-A with the use of genome-wide analyses Polar body biopsy One trial used polar body biopsy with array comparative genomic hybridisation (aCGH). It is uncertain whether the addition of PGT-A by polar body biopsy increases the cLBR compared to IVF without PGT-A (odds ratio (OR) 1.05, 95% confidence interval (CI) 0.66 to 1.66, 1 RCT, N = 396, low-quality evidence). The evidence suggests that for the observed cLBR of 24% in the control group, the chance of live birth following the results of one IVF cycle with PGT-A is between 17% and 34%. It is uncertain whether the LBR after the first embryo transfer improves with PGT-A by polar body biopsy (OR 1.10, 95% CI 0.68 to 1.79, 1 RCT, N = 396, low-quality evidence). PGT-A with polar body biopsy may reduce miscarriage rate (OR 0.45, 95% CI 0.23 to 0.88, 1 RCT, N = 396, low-quality evidence). No data on ongoing pregnancy rate were available. The effect of PGT-A by polar body biopsy on improving clinical pregnancy rate is uncertain (OR 0.77, 95% CI 0.50 to 1.16, 1 RCT, N = 396, low-quality evidence). Blastocyst stage biopsy One trial used blastocyst stage biopsy with next-generation sequencing. It is uncertain whether IVF with the addition of PGT-A by blastocyst stage biopsy increases cLBR compared to IVF without PGT-A, since no data were available. It is uncertain if LBR after the first embryo transfer improves with PGT-A with blastocyst stage biopsy (OR 0.93, 95% CI 0.69 to 1.27, 1 RCT, N = 661, low-quality evidence). It is uncertain whether PGT-A with blastocyst stage biopsy reduces miscarriage rate (OR 0.89, 95% CI 0.52 to 1.54, 1 RCT, N = 661, low-quality evidence). No data on ongoing pregnancy rate or clinical pregnancy rate were available. IVF with PGT-A versus IVF without PGT-A with the use of FISH for the genetic analysis Eleven trials were included in this comparison. It is uncertain whether IVF with addition of PGT-A increases cLBR (OR 0.59, 95% CI 0.35 to 1.01, 1 RCT, N = 408, low-quality evidence). The evidence suggests that for the observed average cLBR of 29% in the control group, the chance of live birth following the results of one IVF cycle with PGT-A is between 12% and 29%. PGT-A performed with FISH probably reduces live births after the first transfer compared to the control group (OR 0.62, 95% CI 0.43 to 0.91, 10 RCTs, N = 1680, I² = 54%, moderate-quality evidence). The evidence suggests that for the observed average LBR per first transfer of 31% in the control group, the chance of live birth after the first embryo transfer with PGT-A is between 16% and 29%. There is probably little or no difference in miscarriage rate between PGT-A and the control group (OR 1.03, 95%, CI 0.75 to 1.41; 10 RCTs, N = 1680, I² = 16%; moderate-quality evidence). The addition of PGT-A may reduce ongoing pregnancy rate (OR 0.68, 95% CI 0.51 to 0.90, 5 RCTs, N = 1121, I² = 60%, low-quality evidence) and probably reduces clinical pregnancies (OR 0.60, 95% CI 0.45 to 0.81, 5 RCTs, N = 1131; I² = 0%, moderate-quality evidence).

AUTHORS' CONCLUSIONS

There is insufficient good-quality evidence of a difference in cumulative live birth rate, live birth rate after the first embryo transfer, or miscarriage rate between IVF with and IVF without PGT-A as currently performed. No data were available on ongoing pregnancy rates. The effect of PGT-A on clinical pregnancy rate is uncertain. Women need to be aware that it is uncertain whether PGT-A with the use of genome-wide analyses is an effective addition to IVF, especially in view of the invasiveness and costs involved in PGT-A. PGT-A using FISH for the genetic analysis is probably harmful. The currently available evidence is insufficient to support PGT-A in routine clinical practice.

ALWAYS ICSI? A SWOT analysis

PURPOSE

Intracytroplasmatic sperm injection (ICSI) is a common procedure used to improve reproductive results, even among couples without male factor infertility. However, the evidence available is still uncertain on the possible advantages and deficiencies that this procedure may have in patients with no formal indication for ICSI.

METHODS

A SWOT (strengths, weaknesses, opportunities, threats) analysis examines the possible advantages and deficiencies of performing ICSI in these patients with no formal indication.

RESULTS

The evidence suggests that ICSI is not justified for non-male factor infertile couples requiring in vitro conception. One of the major strengths associated to the procedure is the virtual elimination of cases further complicated by total fertilization failure and a combination between IVF and ICSI on sibling oocytes has been advised in the literature. Greater technical difficulties, higher costs and performing an unnecessary invasive technique in some cases represent some of the weaknesses of the procedure, and questions regarding safety issues should not be ruled out.

CONCLUSION

Despite the widespread use of ICSI in patients without a formal diagnosis of male factor infertility, evidence demonstrating its effectiveness in this population is still lacking. Additional large and well-designed randomized controlled trials are needed to clarify definitive indications for ICSI in non-male factor infertility.

Preimplantation Genetic Testing for Monogenic Kidney Disease

BACKGROUND AND OBJECTIVES

A genetic cause can be identified for an increasing number of pediatric and adult-onset kidney diseases. Preimplantation genetic testing (formerly known as preimplantation genetic diagnostics) is a reproductive technology that helps prospective parents to prevent passing on (a) disease-causing mutation(s) to their offspring. Here, we provide a clinical overview of 25 years of preimplantation genetic testing for monogenic kidney disease in The Netherlands.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This is a retrospective cohort study of couples counseled on preimplantation genetic testing for monogenic kidney disease in the national preimplantation genetic testing expert center (Maastricht University Medical Center+) from January 1995 to June 2019. Statistical analysis was performed through chi-squared tests.

RESULTS

In total, 98 couples were counseled regarding preimplantation genetic testing, of whom 53% opted for preimplantation genetic testing. The most frequent indications for referral were autosomal dominant polycystic kidney disease (38%), Alport syndrome (26%), and autosomal recessive polycystic kidney disease (9%). Of couples with at least one preimplantation genetic testing cycle with oocyte retrieval, 65% experienced one or more live births of an unaffected child. Of couples counseled, 38% declined preimplantation genetic testing for various personal and technical reasons.

CONCLUSIONS

Referrals, including for adult-onset disease, have increased steadily over the past decade. Though some couples decline preimplantation genetic testing, in the couples who proceed with at least one preimplantation genetic testing cycle, almost two thirds experienced at least one live birth rate.

Haplotyping by linked-read sequencing (HLRS) of the genetic disease carriers for preimplantation genetic testing without a proband or relatives

BACKGROUND

In order to mitigate the risk of allele dropout (ADO) and ensure the accuracy of preimplantation genetic testing for monogenic disease (PGT-M), it is necessary to construct parental haplotypes. Typically, haplotype resolution is obtained by genotyping multiple polymorphic markers in both parents and a proband or a relative. Sometimes, single sperm typing, or tests on the polar bodies may also be useful. Nevertheless, this process is time-consuming. At present, there was no simple linkage analysis strategy for patients without affected relatives.

METHOD

To solve this problem, we established a haplotyping by linked-read sequencing (HLRS) method without the requirement for additional relatives. First, the haplotype of the genetic disease carriers in the family was constructed by linked-read sequencing, and then the informative single nucleotide polymorphisms (SNPs) in upstream and downstream mutation region were selected to construct the embryo haplotype and to determine whether the embryo was carrying the mutation. Two families were selected to validate this method; one with alpha thalassemia and the other with NDP gene disorder.

RESULTS

The haplotyping by linked-read sequencing (HLRS) method was successfully applied to construct parental haplotypes without recruiting additional family members; the method was also validated for PGT-M. The mutation carriers in these families were sequenced by linked-read sequencing, and their haplotypes were successfully phased. Adjacent SNPs of the mutation gene were identified. The informative SNPs were chosen for linkage analyses to identify the carrier embryos. For the alpha thalassemia family, a normal blastocyst was transferred to the uterus and the accuracy of PGT-M was confirmed by amniocentesis at 16 weeks of gestation.

CONCLUSIONS

Our results suggest that HLRS can be applied for PGT-M of monogenic disorders or de novo mutations where the mutations haplotype cannot be determined due to absence of affected relatives.

A whole-genome sequencing-based novel preimplantation genetic testing method for de novo mutations combined with chromosomal balanced translocations

PURPOSE

To explore a new preimplantation genetic testing (PGT) method for de novo mutations (DNMs) combined with chromosomal balanced translocations by whole-genome sequencing (WGS) using the MGISEQ-2000 sequencer.

METHODS

Two families, one with maternal Olmsted syndrome caused by DNM (c.1246C>T) in TRPV3 and a paternal Robertsonian translocation and one with paternal Marfan syndrome caused by DNM (c.4952_4955delAATG) in FBN1 and a maternal reciprocal translocation, underwent PGT for monogenetic disease (PGT-M), chromosomal aneuploidy, and structural rearrangement. WGS of embryos and family members were performed. Bioinformatics analysis based on gradient sequencing depth was performed, and parent-embryo haplotyping was conducted for DNM diagnosis. Sanger sequencing, karyotyping, and chromosomal microarray analysis were performed using an amniotic fluid sample to confirm the PGT results.

RESULTS

After 1 PGT cycle, WGS of 2 embryos from the Olmsted syndrome family revealed euploid embryos without DNMs; after 2 cycles, the 11 embryos from the Marfan syndrome family showed only 1 normal embryo without DNM, copy number variations (CNVs), or aneuploidy. Moreover, 1 blastocyst from the Marfan syndrome family was transferred back to the uterus; the amniocentesis test results were confirmed by PGT and a healthy infant was born.

CONCLUSIONS

WGS based on parent-embryo haplotypes was an effective strategy for PGT of DNMs combined with a chromosomal balanced translocation. Our results indicate this is a reliable and effective diagnostic method that is useful for clinical application in PGT of patients with DNMs.

Factors influencing the clinical outcome of preimplantation genetic testing for polycystic kidney disease

STUDY QUESTION

What are the factors influencing the success rate for couples undergoing preimplantation genetic testing (PGT) for polycystic kidney disease (PKD)?

SUMMARY ANSWER

In our study cohort, the live birth delivery rate is significantly associated with female age while the male infertility accompanying autosomal dominant PKD (ADPKD) does not substantially affect the clinical outcome.

WHAT IS KNOWN ALREADY

While women with ADPKD have no specific fertility problems, male ADPKD patients may present with reproductive system abnormalities and infertility.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort study involves 91 PGT cycles for PKD for 43 couples (33 couples for PKD1, 2 couples for PKD2 and 8 couples for autosomal recessive PKD (ARPKD)) from January 2005 until December 2016 with follow-up of transfers until end of 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Sixteen single-cell clinical tests for PKD based on multiplex PCR of short tandem repeat markers, with or without a specific mutation were developed and applied for diagnosis of 584 Day 3 cleavage stage embryos. In 18 couples, the male partner was affected with ADPKD (=Group A) and 12 of them had a documented infertility status. Group A underwent 52 cycles to oocyte retrieval. For 18 other couples, the female partner was affected with ADPKD (=Group B) and four male partners from this group had a documented history of infertility. This group underwent 31 cycles to OR.

MAIN RESULTS AND THE ROLE OF CHANCE

Genetic analysis resulted in 545 embryos (93.3%) with a diagnosis, of which 215 (36.8%) were genetically transferable. Transfer of 74 embryos in 53 fresh cycles and of 34 cryopreserved embryos in 33 frozen-warmed embryo transfer cycles resulted in a live birth delivery rate of 38.4% per transfer with 31 singleton live births, two twin live births and one ongoing pregnancy. The observed cumulative delivery rate was 57.8% per couple after five treatment cycles. Thirty cryopreserved embryos still remain available for transfer. The clinical pregnancy rate per transfer (fresh + frozen; 45.9% in group A versus 60.0% in group B, P < 0.05) and the live birth delivery rate per transfer (fresh + frozen; 27.0% in group A versus 42.9% in group B, P < 0.05) was significantly lower for couples with the male partner affected with ADPKD compared with couples with the female partner affected with ADPKD. However, a multivariate logistic regression analysis showed that only female age was associated with live birth delivery rate (odds ratio = 0.87; 95% CI: 0.77-0.99; P = 0.032).

LIMITATIONS, REASONS FOR CAUTION

This study is based on retrospective data from a single centre with Day 3 one-cell and two-cell biopsy. Further analysis of a larger cohort of PKD patients undergoing PGT is required to determine the impact of male infertility associated with ADPKD on the cumulative results.

WIDER IMPLICATIONS OF THE FINDINGS

Knowledge about factors affecting the clinical outcome after PGT can be a valuable tool for physicians to counsel PKD patients about their reproductive options. Males affected with ADPKD who suffer from infertility should be advised to seek treatment in time to improve their chances of conceiving a child.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was obtained. There are no competing interests to declare.

TRIAL REGISTRATION NUMBER

Not applicable.

The impact of parental unaffected allele combination on the diagnostic outcome in the preimplantation genetic testing for myotonic dystrophy type 1 in Japanese ancestry

PURPOSE

The objective is to clarify the practical problem of the preimplantation genetic testing (PGT) for myotonic dystrophy type 1 (DM1) in Japanese subjects.

METHODS

For the 32 couples who consented to participate in PGT for DM1, CTG repeats number on the unaffected alleles was analyzed. Based on the allele combination, they were classified into 3 groups by the number of diagnostic allelic pattern; "full informative," "semi informative," and "noninformative." According to the Japan Society of Obstetrics and Gynecology (JSOG) principle, PGT was performed using the direct diagnosis to the 288 embryos from the 17 couples who received the ethical approval from both our institution and JSOG.

RESULTS

In the 32 couples, the frequency of CTG repeats on the unaffected alleles showed bimodal distribution. The "full informative," "semi informative," and "noninformative" couples accounted for 46.9% (15/32 couples), 46.9% (15/32 couples) and 6.2% (2/32 couples), respectively. The transferable embryos accounted for 28.9% (33/114 embryos) in the "full informative" couples, although it was limited to 12.6% (22/174 embryos) in the "semi informative" couples.

CONCLUSION

The loss of unaffected embryos which cannot be diagnosed as transferable was a clinically major problem and implied an increase in oocyte retrieval, especially for "semi informative" couples.

ESHRE PGT Consortium good practice recommendations for the detection of monogenic disorders

The field of preimplantation genetic testing (PGT) is evolving fast and best practice advice is essential for regulation and standardisation of diagnostic testing. The previous ESHRE guidelines on best practice for PGD, published in 2005 and 2011, are considered outdated, and the development of new papers outlining recommendations for good practice in PGT was necessary. The current paper provides recommendations on the technical aspects of PGT for monogenic/single-gene defects (PGT-M) and covers recommendations on basic methods for PGT-M and testing strategies. Furthermore, some specific recommendations are formulated for special cases, including de novo pathogenic variants, consanguineous couples, HLA typing, exclusion testing and disorders caused by pathogenic variants in the mitochondrial DNA. This paper is one of a series of four papers on good practice recommendations on PGT. The other papers cover the organisation of a PGT centre, embryo biopsy and tubing and the technical aspects of PGT for chromosomal structural rearrangements/aneuploidies. Together, these papers should assist scientists interested in PGT in developing the best laboratory and clinical practice possible.

ESHRE PGT Consortium good practice recommendations for the organisation of PGT

The field of preimplantation genetic testing (PGT) is evolving fast, and best practice advice is essential for regulation and standardisation of diagnostic testing. The previous ESHRE guidelines on best practice for preimplantation genetic diagnosis, published in 2005 and 2011, are considered outdated and the development of new papers outlining recommendations for good practice in PGT was necessary. The current updated version of the recommendations for good practice is, similar to the 2011 version, split into four documents, one of which covers the organisation of a PGT centre. The other documents focus on the different technical aspects of embryo biopsy, PGT for monogenic/single-gene defects (PGT-M) and PGT for chromosomal structural rearrangements/aneuploidies (PGT-SR/PGT-A). The current document outlines the steps prior to starting a PGT cycle, with details on patient inclusion and exclusion, and counselling and information provision. Also, recommendations are provided on the follow-up of PGT pregnancies and babies. Finally, some further recommendations are made on the practical organisation of an IVF/PGT centre, including basic requirements, transport PGT and quality management. This document, together with the documents on embryo biopsy, PGT-M and PGT-SR/PGT-A, should assist everyone interested in PGT in developing the best laboratory and clinical practice possible.

ESHRE PGT Consortium and SIG Embryology good practice recommendations for polar body and embryo biopsy for PGT

The field of preimplantation genetic testing (PGT) is evolving fast, and best practice advice is essential for regulation and standardisation of diagnostic testing. The previous ESHRE guidelines on best practice for PGD, published in 2005 and 2011, are considered outdated, and the development of new papers outlining recommendations for good practice in PGT was necessary.

The current paper provides recommendations on the technical aspects of embryo biopsy and covers recommendations on the biopsy procedure, cryopreservation and laboratory issues and training, in addition to technical aspects and strengths and limitations specific for currently used techniques at different stages (polar body, cleavage stage and blastocyst biopsy). Furthermore, alternative sampling methods are briefly described.This paper is one of a series of four papers on good practice recommendations on PGT. The other papers cover the organisation of PGT, and the different technical aspects of PGT for monogenic/single-gene defects (PGT-M) and PGT for chromosomal structural rearrangements/aneuploidies (PGT-SR/PGT-A).

Together, these papers should assist everyone interested in PGT in developing the best laboratory and clinical practice possible.

ESHRE PGT Consortium good practice recommendations for the detection of structural and numerical chromosomal aberrations

The field of preimplantation genetic testing (PGT) is evolving fast, and best practice advice is essential for regulation and standardisation of diagnostic testing. The previous ESHRE guidelines on best practice for PGD, published in 2005 and 2011, are considered outdated, and the development of new papers outlining recommendations for good practice in PGT was necessary. The current paper provides recommendations on the technical aspects of PGT for chromosomal structural rearrangements (PGT-SR) and PGT for aneuploidies (PGT-A) and covers recommendations on array-based comparative genomic hybridisation (aCGH) and next-generation sequencing (NGS) for PGT-SR and PGT-A and on fluorescence in situ hybridisation (FISH) and single nucleotide polymorphism (SNP) array for PGT-SR, including laboratory issues, work practice controls, pre-examination validation, preclinical work-up, risk assessment and limitations. Furthermore, some general recommendations on PGT-SR/PGT-A are formulated around training and general risk assessment, and the examination and post-examination process. This paper is one of a series of four papers on good practice recommendations on PGT. The other papers cover the organisation of a PGT centre, embryo biopsy and tubing and the technical aspects of PGT for monogenic/single-gene defects (PGT-M). Together, these papers should assist everyone interested in PGT in developing the best laboratory and clinical practice possible.

Preimplantation Genetic Testing for Chromosomal Abnormalities: Aneuploidy, Mosaicism, and Structural Rearrangements

There is a high incidence of chromosomal abnormalities in early human embryos, whether they are generated by natural conception or by assisted reproductive technologies (ART). Cells with chromosomal copy number deviations or chromosome structural rearrangements can compromise the viability of embryos; much of the naturally low human fecundity as well as low success rates of ART can be ascribed to these cytogenetic defects. Chromosomal anomalies are also responsible for a large proportion of miscarriages and congenital disorders. There is therefore tremendous value in methods that identify embryos containing chromosomal abnormalities before intrauterine transfer to a patient being treated for infertility—the goal being the exclusion of affected embryos in order to improve clinical outcomes. This is the rationale behind preimplantation genetic testing for aneuploidy (PGT-A) and structural rearrangements (-SR). Contemporary methods are capable of much more than detecting whole chromosome abnormalities (e.g., monosomy/trisomy). Technical enhancements and increased resolution and sensitivity permit the identification of chromosomal mosaicism (embryos containing a mix of normal and abnormal cells), as well as the detection of sub-chromosomal abnormalities such as segmental deletions and duplications. Earlier approaches to screening for chromosomal abnormalities yielded a binary result of normal versus abnormal, but the new refinements in the system call for new categories, each with specific clinical outcomes and nuances for clinical management. This review intends to give an overview of PGT-A and -SR, emphasizing recent advances and areas of active development.

Birth of a healthy boy following preimplantation genetic diagnosis for congenital adrenal hyperplasia

Classical 3β-HSD deficiency due to mutations in the HSD3B2 gene is responsible for a rare form of congenital adrenal hyperplasia (CAH) and is identified by varying degrees of salt wasting. Preimplantation genetic diagnosis (PGD) was performed in a couple carrying mutation c.690 G>A in the HSD3B2 gene. Four polymorphic short tandem repeat markers closely linked to the HSD3B2 gene (D1S185, D1S453, D1S514, D1S540) for linkage analysis in conjunction with the direct mutation analysis were used in embryo genotyping. Two CODIS STRs (VWA and THO1) were also used to confirm embryo zygosity and rule out possible contaminations. Finally, SRY and AMYLOGENIN markers were used for embryo sex determination. PGD was performed by fluorescent multiplex seminested polymerase chain reaction and sequencing. Six embryos were tested and one male carrier embryo was transferred, resulting in the birth of a healthy boy.

Preimplantation genetic testing with HLA matching: from counseling to birth and beyond

Preimplantation genetic testing-human leukocyte antigen '(PGT-HLA) only' refers to the HLA typing of single or few cells biopsied from in vitro fertilized preimplantation embryos. The aim of the procedure is to establish a pregnancy, in which the fetus is HLA compatible with an affected sibling in need of a hematopoietic stem cell transplantation (HSCT). During PGT-M-HLA, the identification of a HLA-compatible embryo is combined with the detection of mutation(s) underlying immunodeficiencies and hemoglobinopathies. We report a combined retrospective and prospective cohort analysis of PGT-(M-)HLA procedures carried out from 1998 until 2017, with follow-up of transplantations to 2019. During the study period, 234 couples from 22 countries were invited for a multidisciplinary consultation. Two couples were rejected and 70 couples declined (various reasons), leaving 162 couples for which 414 clinical cycles were carried out. Cleavage stage biopsy followed by single-cell multiplex PCR for short tandem repeat-based haplotyping was applied in most cases (98.7%). The diagnostic efficiency was high (94.8%) but only 16.5% of the embryos was genetically suitable for transfer. Fresh and frozen-thawed embryo transfer resulted in 67 clinical pregnancies, 63 deliveries, and 74 live births, of which 60 children were HLA compatible. This yielded a live birth delivery rate of 30.3% per transfer. Information on neonatal characteristics of the matching PGT-(M-)HLA children showed reassuring outcomes. So far, HSCT was carried out successfully for 25 out of 26 cases. In conclusion, our data show that PGT-(M-)HLA is a valuable procedure: the high complexity and limited delivery rate are balanced by the successful HSCT outcome and the positive impact on families.

Pregnancy in Advanced Kidney Disease: Clinical Practice Considerations on a Challenging Combination

BACKGROUND

Thanks to the advances in care, pregnancy is now attainable for the majority of young female CKD patients, although it is still a high-risk endeavor. Clinical decision-making in these cases is impacted by a myriad of factors, making (pre)pregnancy counseling a complex process. The complexities, further impacted by limited data and unknown risks regarding outcome, can cause discussions when deciding on the best care for a specific patient.

OBJECTIVES

In this article, we provide an overview of the considerations and dilemmas we encounter in preconception counseling and offer our perspective on how to deal with them in daily clinical practice.

METHODS

The main topics we discuss in our counseling are (1) the high risk of pregnancy complications, (2) the risk of permanent CKD deterioration due to pregnancy and subsequent decreased life expectancy, (3) appropriate changes in renal medication, and (4) assisted reproduction, genetic testing, and prenatal or preimplantation genetic diagnostics.

RESULTS AND CONCLUSIONS

In our clinic, we openly address moral dilemmas arising in clinical practice in pregnancy and CKD, both within the physician team and with the patient. We do this by ensuring an interpretive physician-patient interaction and shared decision-making, deliberating in a multidisciplinary setting and, if needed, with input from an expert committee.

Fertility preservation in BRCA mutation carriers-efficacy and safety issues: a review

BRCA mutation carriers face various situations that influence their fertility potential. There is still a lack of guideline or expert consensus on Fertility Preservation (FP) in BRCA mutation carriers and the necessity and safety of FP in BRCA mutation carriers is still in dispute. This review aims to focus on the population of BRCA mutation carriers by analyzing the existing FP strategies, comprehensively comparing the pros and cons of each strategy and its applicability.FP is a suggestion for BRCA mutation carriers with birth planning. Different FP strategies have different characteristics. Considering the particularity of BRCA mutation carriers, multiple factors need to be carefully considered. This review focuses on the applicability of each FP method for carriers under various circumstances. Available FP strategies including oocyte cryopreservation, ovarian tissue cryopreservation, preimplantation genetic diagnosis, and egg/embryo donation are analyzed by comparing existing methods comprehensively. In the attempt to provide an up-to-date decision-making guidance. Conditions taking into consideration were the carrier's age, the risk of breast and ovarian metastasis, plans for oncotherapy, FP outcome, time available for FP intervention and accessibility.Overall, FP is necessary and safe for BRCA mutation carriers. Among all available FP methods, oocyte cryopreservation is the most reliable procedure; ovarian tissue cryopreservation is the only way for preserving both fertility and endocrine function, recommended for pre-pubertal carriers and when time is limited for oocyte stimulation. A clear framework provides frontline clinical practitioners a new thought and eventually benefit thousands of BRCA mutation carriers.

The outcomes after transfers of embryos with chromosomal mosaicism: a single reproductive medicine center experience at iVF Riga clinic

Aim: The aim of this study is to summarize the outcomes of transfers of mosaic embryos, which were classified according to guidelines and in strong collaboration of reproductologists, clinical geneticists and patients approved as suitable for transfer. Material and Methods: Retrospective data were collected from 70 patients from a private IVF center to whom embryos with mosaic changes in chromosomal material were transferred from 2015 to 2019. Results and Conclusion: Implantation outcomes and continuing pregnancies showed slight differences, when compared to fully normal embryos. Artifacts have to be differentiated from undeniable aberrations, and correct interpretation of results must be done with following patient counselling and prenatal testing if necessary.

Preimplantation genetic diagnosis (PGD) and genetic testing for aneuploidy (PGT-A): status and future challenges

The world's first in vitro fertilization (IVF) baby was born in July 1978 in the UK. Since then, more than 7 million infants have been born worldwide as a result of IVF. Preimplantation genetic diagnosis (PGD) was introduced in the late 1980s for couples at risk of transmitting a genetic abnormality to their children. From the mid-1990s, this technology has been employed as an embryo selection tool for patients undergoing IVF and has been known as preimplantation genetic screening (PGS). The aim of this practice has been to identify and select euploid embryos for transfer, in order to increase efficacy of IVF cycle, ensure higher implantation rates or at least decreased time to pregnancy. In the early days, fluorescent in situ hybridization (FISH) technology was used for genetic analysis. New advancements in both biopsy and cytogenetic have made possible the improvement of PGD and PGT-A analysis. Currently, a variety of technologies have been implemented to individuate euploid embryos to be preferentially transferred in IVF treatments. The purpose of this review is to clarify the differences between PGD and PGT-A, and to discuss current indications and requirements for embryo biopsy and genetic methodologies used.

Preimplantation Genetic Testing of Multiple Endocrine Neoplasia Type 2A

Background: When discussing matters of reproduction, the 2015 revised guidelines for the management of medullary thyroid carcinoma recommend that patients diagnosed with multiple endocrine neoplasia type 2A (MEN 2A) are informed about the option of Preimplantation Genetic Testing for Monogenic Disorders (PGT-M). In addition, patients seem to have a genuine interest in reproductive options. However, there are just two reports worldwide of this technology being used for patients with MEN 2A. We here present, in a Danish couple where the man has MEN 2A, the first European family with children born after PGT-M. Objective: To report the results of PGT-M in relation to multiple endocrine neoplasia type 2A with the aim to increase awareness among physicians treating this and other genetic disorders. Methods: A Danish couple was referred to the PGT Center at Copenhagen University Hospital Rigshospitalet and opted for PGT-M after counseling by a clinical geneticist and a fertility doctor. The embryos were diagnosed using microsatellite polymorphic marker close to RET. Results: The couple had two healthy children born in 2017 and 2019 as a result of a total of three ICSI treatments including controlled ovarian stimulation, oocyte retrieval and PGT-M, and a total of six blastocyst transfers. Conclusion: A session with a clinical geneticist covering all reproductive options for patients in early adult life is a relevant part of the clinical management of patients with MEN 2A, and other patients with hereditary cancer predisposition syndromes.

Birth of a healthy baby after preimplantation genetic diagnosis in a carrier of mucopolysaccharidosis type II: The first case in Korea

Mucopolysaccharidosis type II (MPS II) is a rare X-linked recessive lysosomal storage disease caused by mutation of the iduronate-2-sulfatase gene. The mutation results in iduronate-2-sulfatase deficiency, which causes the progressive accumulation of heparan sulfate and dermatan sulfate in cellular lysosomes. The phenotype, age of onset, and symptoms of MPS II vary; accordingly, the disease can be classified into either the early-onset type or the late-onset type, depending on the age of onset and the severity of the symptoms. In patients with severe MPS II, symptoms typically first appear between 2 and 5 years of age. Patients with severe MPS II usually die in the second decade of life although some patients with less severe disease have survived into their fifth or sixth decade. Here, we report the establishment of a preimplantation genetic diagnosis (PGD) strategy using multiplex nested polymerase chain reaction, direct sequencing, and linkage analysis. Unaffected embryos were selected via the diagnosis of a single blastomere, and a healthy boy was delivered by a female carrier of MPS II. This is the first successful application of PGD in a patient with MPS II in Korea

Clinical utility of combined preimplantation genetic testing methods in couples at risk of passing on beta thalassemia/hemoglobin E disease: A retrospective review from a single center

Thalassemia and hemoglobinopathy is a group of hereditary blood disorder with diverse clinical manifestation inherited by autosomal recessive manner. The Beta thalassemia/Hemoglobin E disease (HbE/βthal) causes a variable degree of hemolysis and the most severe form of HbE/βthal disease develop a lifelong transfusion-dependent anemia. Preimplantation genetic testing (PGT) is an established procedure of embryo genetic analysis to avoid the risk of passing on this particular condition from the carrier parents to their offspring. Preimplantation genetic testing for chromosomal aneuploidy (PGT-A) also facilitates the selection of embryos without chromosomal aberration resulting in the successful embryo implantation rate. Herein, we study the clinical outcome of using combined PGT-M and PGT-A in couples at risk of passing on HbE/βthal disease. The study was performed from January 2016 to December 2017. PGT-M was developed using short tandem repeat linkage analysis around the beta globin gene cluster and direct mutation testing using primer extension-based mini-sequencing. Thereafter, we recruited 15 couples at risk of passing on HbE/βthal disease who underwent a combined total of 22 IVF cycles. PGT was performed in 106 embryos with a 3.89% allele drop-out rate. Using combined PGT-M and PGT-A methods, 80% of women obtained satisfactory genetic testing results and were able to undergo embryo transfer within the first two cycles. The successful implantation rate was 64.29%. PGT accuracy was evaluated by prenatal and postnatal genetic confirmation and 100% had a genetic status consistent with PGT results. The overall clinical outcome of successful live birth for couples at risk of producing offspring with HbE/βthal was 53.33%. Conclusively, combined PGT-M and PGT-A is a useful technology to prevent HbE/βthal disease in the offspring of recessive carriers.

Präimplantationsdiagnostik für monogene Erkrankungen am PID-Zentrum Regensburg

Wir berichten über die Erfahrungen unseres PID-Zentrums bei der Präimplantationsdiagnostik (PID) für 149 Familien mit hohem Risiko für eine monogene Erkrankung bei den Nachkommen und die Ergebnisse aus 316 PID-Zyklen. Seit 2001 wurden bei uns insgesamt 251 Diagnostikzyklen mittels Polkörperdiagnostik (PKD) durchgeführt. Nach der Zulassung unserer Gruppe als PID-Zentrum im Juni 2015 haben wir inzwischen für 45 Familien insgesamt 65 Trophektoderm-Diagnostikzyklen (TED) nach Trophektoderm (TE)-Biopsie durchgeführt (1,4/Familie). Unsere vorläufigen Daten bestätigen eine hohe Diagnoseeffizienz beider Verfahren mit Verdopplung der klinischen Schwangerschaftsrate pro Transfer nach TED auf 48,2 % verglichen mit 22,9 % nach PKD. Bei einer durchschnittlichen Rate von 4,3 verfügbaren Blastozysten pro TED-Zyklus ist die Rate von Zyklen ohne transferierbare Embryonen mit 27,7 % (für 6/45 Familien = 13,3 %) erwartungsgemäß höher als bei der PKD (14,7 %) für durchschnittlich 8 Eizellen pro Zyklus mit erfolgreicher Biopsie beider Polkörper. Schon mit dem ersten Transfer konnte jedoch nach TED für 55,3 % der Paare eine klinische Schwangerschaft erreicht werden. Insgesamt ermöglichte die TED kumulativ nach durchschnittlich 1,4 Transferen eine klinische Schwangerschaft für 68,5 % der Familien mit Transfer und insgesamt eine schonendere Behandlung mit weniger TED-Zyklen (PKD: kumulativ 40,3 % nach 2,3 Transferen), weniger Hormonstimulationen und entsprechend auch geringeren Kosten. Insbesondere die Subgruppe der weiblichen Überträgerinnen von Repeaterkrankungen mit insgesamt niedrigeren Erfolgschancen scheint nach unseren vorläufigen Daten von der TED zu profitieren.

The evolving role of genetic tests in reproductive medicine

Infertility is considered a major public health issue, and approximately 1 out of 6 people worldwide suffer from infertility during their reproductive lifespans. Thanks to technological advances, genetic tests are becoming increasingly relevant in reproductive medicine. More genetic tests are required to identify the cause of male and/or female infertility, identify carriers of inherited diseases and plan antenatal testing. Furthermore, genetic tests provide direction toward the most appropriate assisted reproductive techniques. Nevertheless, the use of molecular analysis in this field is still fragmented and cumbersome. The aim of this review is to highlight the conditions in which a genetic evaluation (counselling and testing) plays a role in improving the reproductive outcomes of infertile couples. We conducted a review of the literature, and starting from the observation of specific signs and symptoms, we describe the available molecular tests. To conceive a child, both partners' reproductive systems need to function in a precisely choreographed manner. Hence to treat infertility, it is key to assess both partners. Our results highlight the increasing importance of molecular testing in reproductive medicine.

Robust Preimplantation Genetic Testing Strategy for Myotonic Dystrophy Type 1 by Bidirectional Triplet-Primed Polymerase Chain Reaction Combined With Multi-microsatellite Haplotyping Following Whole-Genome Amplification

Myotonic dystrophy type 1 (DM1) is caused by expansion of the DMPK CTG trinucleotide repeat. Disease transmission to offspring can be avoided through prenatal diagnosis or preimplantation genetic testing for monogenic disorders (PGT-M). We describe a robust strategy for DM1 PGT-M that can be applied to virtually any at-risk couple. This strategy utilizes whole-genome amplification, followed by triplet-primed PCR (TP-PCR) detection of expanded DMPK alleles, in parallel with single-tube haplotype analysis of 12 closely linked and highly polymorphic microsatellite markers. Bidirectional TP-PCR and dodecaplex marker PCR assays were optimized and validated on whole-genome amplified single lymphoblasts isolated from DM1 reference cell lines, and tested on a simulated PGT-M case comprising a parent-offspring trio and three simulated embryos. Bidirectional DMPK TP-PCR reliably detects repeat expansions even in the presence of non-CTG interruptions at either end of the expanded allele. Misdiagnoses, diagnostic ambiguity, and couple-specific assay customization are further minimized by the use of multi-marker haplotyping, preventing the loss of potentially unaffected embryos for transfer.

Preimplantation genetic testing for monogenic diseases: a Brazilian IVF centre experience

OBJECTIVE

To describe the cases of preimplantation genetic testing for monogenic diseases (PGT-M) in fertile couples who had undergone intracytoplasmic sperm injection (ICSI) cycles in a Brazilian in vitro fertilisation (IVF) centre and determine whether these cases were different from those reported from the European Society of Human Reproduction and Embryology (ESHRE).

METHODS

This retrospective collection included data obtained from ICSI-PGT-M cycles between 2011 and 2016. The disease indication, number of biopsied embryos, biopsy stage, diagnosed and affected embryos, and cycles with embryo to transfer as well as implantation, pregnancy and miscarriage rates were analysed and compared to cycles without genetic diagnosis (PGT) and with ESHRE PGD Consortium collection XIV-XV.

RESULTS

From 5,070 cycles performed, 72 had indications for PGT-M. The most common time for biopsy was cleavage-stage; 93% of the embryos had a diagnostic result, 59.4% of which were genetically transferable, resulting in 68% of the cycles with transferred embryos, a 22.1% implantation rate, and a 28.6% pregnancy rate. No differences in clinical outcomes of cycles with PGT-M or without PGT were observed. The day of biopsy and diagnostic success as well as implantation, pregnancy and miscarriage rates were similar to ESHRE collection.

CONCLUSIONS

Although the proportion of cases with PGT-M was low, its efficacy was similar to what was reported in the European collection and represents a viable alternative for families at risk of transmitting a genetic disorder to their offspring. The main difference between our and ESHRE collection were the disease indications, which reflected the admixed, multi-ethnic Brazilian population.

Preimplantation Genetic Diagnosis of Neurodegenerative Diseases: Review of Methodologies and Report of Our Experience as a Regional Reference Laboratory

Preimplantation genetic diagnosis (PGD) has become a crucial approach in helping carriers of inherited disorders to give birth to healthy offspring. In this study, we review PGD methodologies and explore the use of amplification refractory mutation system quantitative polymerase chain reaction (ARMS-qPCR) and/or linkage analysis for PGD in neurodegenerative diseases that are clinically relevant with typical features, such as late onset, and which are severely debilitating. A total of 13 oocyte retrieval cycles were conducted in 10 cases with various neurodegenerative diseases. Among the 59 embryos analyzed, 49.2% (29/59) were unaffected and 50.8% (30/59) were affected. Of the 12 embryo transfer cycles, three resulted in pregnancy, and all pregnancies were delivered. The implantation rate and livebirth rate were 23.1% (3/13) per oocyte retrieval cycle and 25.0% (3/12) per embryo transfer cycle. Allele dropout (ADO) was noted in two embryos that were classified as unaffected by ARMS-qPCR but were evidenced as affected after prenatal diagnosis, rendering the false negative rate as 6.3% (2/32). Four among the 13 cycles underwent PGD by ARMS-qPCR coupled with linkage analysis, and all were correctly diagnosed. We conclude that PGD by ARMS-qPCR and/or linkage analysis is a feasible strategy, whereas ADO is a concern when ARMS-qPCR is used as the sole technology in PGD, especially in autosomal dominant diseases.