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

PURPOSE: The trend of delaying childbirth has resulted in a growing number of advanced-aged women who are opting for preimplantation genetic testing (PGT) to screen for monogenic diseases or structural chromosomal rearrangements (PGT-M and PGT-SR). This increase in demand necessitates the development of a clinical predictive model for live birth outcomes in these women. Therefore, the objective of this study is to construct a comprehensive predictive model that assesses the likelihood of achieving a successful live birth in advanced-aged women undergoing PGT-M and PGT-SR treatments. METHODS: A retrospective cohort study of 37-45-year-old women undergoing preimplantation genetic testing for monogenic disease or structural chromosomal rearrangement cycles from 2010 to 2021 was conducted at a university hospital reproductive centre. The purpose was to develop a clinical predictive model for live birth in these women. The main outcome studied was the cumulative live birth rate in the first or subsequent cycles. Developing a decision tree enabled a comprehensive study of clinical parameters and expected outcomes. RESULTS: The analysis included 158 women undergoing 753 preimplantation genetic testing cycles. The cumulative live birth rate was 37.342% (59/158). Decision tree analysis revealed that women aged ≤ 40.1 or women > 40.1 with one or more top-quality transferable embryos in their first cycle had the best chance for a live baby (56% and 41%, respectively). Those older than 40.1 without top-quality embryos and seven or fewer dominant follicles had no live births. A Kaplan-Meier curve showed that for autosomal dominant diseases, there was a negligible increase in live birth rate after three cycles, compared to six cycles in autosomal recessive inheritance. CONCLUSION: In older women, the chance of delivering after repeated cycles is higher in those with at least one top-quality unaffected embryo in their first preimplantation genetic testing cycle. Additional preimplantation genetic testing cycles after three in carriers of an autosomal dominant disorder and six in those with an autosomal recessive disorder should be considered prudently.

The new face of cystic fibrosis in the era of population genetic carrier screening.

BACKGROUND: Population genetic carrier screening (PGCS) for cystic fibrosis (CF) has been offered to couples in Israel since 1999 and was included in a fully subsidized national program in 2008. We evaluated the impact of PGCS on CF incidence, genetic and clinical features. METHODS: This was a retrospective national study. Demographic and clinical characteristics of children with CF born in Israel between 2008 and 2018 were obtained from the national CF registry and from patients' medical records. Data on CF births, preimplantation genetic testing (PGT), pregnancy termination and de-identified data from the PGCS program were collected. RESULTS: CF births per 100,000 live births decreased from 8.29 in 2008 to 0.54 in 2018 (IRR = 0.84, p < 0.001). The CF pregnancy termination rate did not change (IRR = 1, p=  0.9) while the CF-related PGT rate increased markedly (IRR = 1.33, p < 0.001). One hundred and two children were born with CF between 2008 and 2018 with a median age at diagnosis of 4.8 months, range 0-111 months. Unlike the generally high uptake nationally, 65/102 had not performed PGCS. Even if all had utilized PGCS, only 51 would have been detected by the existing genetic screening panel. Clinically, 34 % of children were pancreatic sufficient compared to 23 % before 2008 (p = 0.04). CONCLUSIONS: Since institution of a nationwide PGCS program, the birth of children with CF decreased markedly. Residual function variants and pancreatic sufficiency were more common. A broader genetic screening panel and increased PGCS utilization may further decrease the birth of children with CF.

A pathogenic variant in the uncharacterized RNF212B gene results in severe aneuploidy male infertility and repeated IVF failure.

Quantitative and qualitative spermatogenic impairments are major causes of men's infertility. Although in vitro fertilization (IVF) is effective, some couples persistently fail to conceive. To identify causal variants in patients with severe male infertility factor and repeated IVF failures, we sequenced the exome of two consanguineous family members who underwent several failed IVF cycles and were diagnosed with low sperm count and motility. We identified a rare homozygous nonsense mutation in a previously uncharacterized gene, RNF212B, as the causative variant. Recurrence was identified in another unrelated, infertile patient who also faced repeated failed IVF treatments. scRNA-seq demonstrated meiosis-specific expression of RNF212B. Sequence analysis located a protein domain known to be associated with aneuploidy, which can explain multiple IVF failures. Accordingly, FISH analysis revealed a high aneuploidy rate in the patients' sperm cells and their IVF embryos. Finally, inactivation of the Drosophila orthologs significantly reduced male fertility. Given that members of the evolutionary conserved RNF212 gene family are involved in meiotic recombination and crossover maturation, our findings indicate a critical role of RNF212B in meiosis, genome stability, and in human fertility. Since recombination is completely absent in Drosophila males, our findings may indicate an additional unrelated role for the RNF212-like paralogs in spermatogenesis.

The association between a carrier state of FMR1 premutation and numeric sex chromosome variations.

PURPOSE: Women carriers of FMR1 premutation are at increased risk of early ovarian dysfunction and even premature ovarian insufficiency. The aim of this study was to examine a possible association between FMR1 permutation and numeric sex chromosome variations. METHODS: A retrospective case-control study conducted in the reproductive center of a university-affiliated medical center. The primary outcome measure was the rate of sex chromosomal numerical aberrations, as demonstrated by haplotype analyses, in FMR1 premutation carriers compared to X-linked preimplantation genetic testing for monogenic/single gene defect (PGT-M) cycles for other indications that do not affect the ovarian follicles and oocytes. RESULTS: A total of 2790 embryos with a final genetic analysis from 577 IVF PGT-M cycles were included in the final analysis. Mean age was similar between the groups, however, FMR1 carriers required more gonadotropins, and more women were poor responders with three or less oocytes collected. The ratio of embryos carrying a numeric sex chromosome variation was similar: 8.3% (138/1668) of embryos in the FMR1 group compared to 7.1% (80/1122) in the controls. A subgroup analysis based on age and response to stimulation has not demonstrated a significant difference either. CONCLUSIONS: Although carriers of FMR1 premutation exhibit signs of reduced ovarian response, it does not seem to affect the rate of numeric sex chromosomal variation compared to women undergoing PGT-M for other indications. This suggests that the mechanism for chromosomal number aberrations in women at advanced maternal age are different to those FMR1 premutation carriers with poor ovarian reserve.

The impact of fragile X premutation carrier status on embryo morphokinetic development.

RESEARCH QUESTION: Does inheritance of the fragile X mental retardation 1 (FMR1) premutation allele affect embryo morphokinetic development? DESIGN: A retrospective cohort analysis of 529 embryos from 126 IVF cycles of 39 FMR1 premutation female carriers undergoing preimplantation genetic testing for monogenic/single gene defects (PGT-M). Morphological and morphokinetic parameters obtained using a time-lapse monitoring system were compared between embryos that inherited the FMR1 premutation allele (FMR1 group, n = 271) and those who received the normal allele (normal group, n = 258). The following embryo outcome measures were compared: morphokinetic parameters up to day 3, start of blastulation time (tSB) for day 5 embryos and the rate of top-quality embryos on days 3 and 5. RESULTS: No differences were found in morphokinetic parameters between the groups from the time of intracytoplasmic sperm injection (ICSI) until a biopsy on day 3. The blastulation rate in the two groups was comparable. However, the start of blastulation was delayed in FMR1 embryos compared to that in the genetically normal embryos (median tSB: 104.2 h [99.3-110.3] versus 101.6 h [94.5-106.7], P = 0.01). In addition, the rate of top-quality FMR1 embryos was lower than that of genetically normal embryos (25.6% versus 38.8%, P = 0.04). CONCLUSION: Embryos that inherit the FMR1 premutation allele are of lower quality at the blastocyst stage compared with those that do not inherit the mutated allele.

Whole Genome Sequencing Applied in Familial Hamartomatous Polyposis Identifies Novel Structural Variations.

Hamartomatous polyposis syndromes (HPS) are rare cancer-predisposing disorders including Juvenile polyposis (JPS), Peutz-Jeghers (PJS) and PTEN hamartomatous syndromes (PHS). Penetrant mutations in corresponding genes (SMAD4, BMPR1A, STK11, PTEN and AKT1), are usually diagnosed via a next-generation-sequencing gene panel (NGS-GP) for tailored surveillance and preimplantation testing for monogenic disorders (PGT-M). Five probands with HPS phenotype, with no genetic diagnosis per genetic workup, underwent whole-genome sequencing (WGS) that identified structural genetic alterations: two novel inversions in BMPRA1 and STK11, two BMPR1A-deletions, known as founders among Bukharan Jews, and BMPR1A microdeletion. BMPR1A inversion was validated by "junction fragment" amplification and direct testing. PGT-M was performed via multiplex-PCR and enabled successful birth of a non-carrier baby. WGS may be considered for HPS patients with no NGS-GP findings to exclude structural alterations.

A decision tree model for predicting live birth in FMR1 premutation carriers undergoing preimplantation genetic testing for monogenic/single gene defects.

RESEARCH QUESTION: Can patient selection for successful preimplantation genetic testing for women who are fragile X (FMR1) premutation carriers be optimized using a decision tree analysis? This decision support tool enables a comprehensive study of a set of clinical parameters and the expected outcomes. DESIGN: A retrospective case-control study analysing the results of 264 fresh and 21 frozen preimplantation genetic testing for monogenic disorders/single gene defects (PGT-M) cycles in 64 FMR1 premutation carriers. Primary outcome was live birth per cycle start. Live birth rate was calculated for the start of the ovarian stimulation cycle. Fresh and frozen embryo transfers from the same cycle were included. RESULTS: The decision tree model showed that the number of cytosine guanine (CGG) repeats was only a moderate predictor for live birth, whereas an age younger than 36 years was the best predictor for live birth, followed by a collection of 14 or more oocytes. These findings were supported by the results of the logistic regression, which found that only age and oocyte number were significantly associated with live birth (P = 0.005 and 0.017, respectively). CONCLUSIONS: The number of CGG repeats is a relatively poor predictor for live birth in PGT-M cycles. FMR1 premutation carriers are no different from non-carriers. Age is the best identifier of live birth, followed by the number of retrieved oocytes.

Fertility preservation and PGT-M in women with familial adenomatous polyposis-associated desmoid tumours.

RESEARCH QUESTION: Is ovarian stimulation and pregnancy in women with familial adenomatous polyposis (FAP)-associated desmoid tumours safe? DESIGN: The study included women with FAP-associated desmoid tumours who underwent fertility treatments at the authors' tertiary medical centre between the years 2011 and 2021. Data were collected from the fertility unit's charts and from the oncological registries. The main outcome measures were the number of vitrified oocytes and embryos, and the number of live births in preimplantation genetic testing for monogenic/single gene defects (PGT-M) cycles. RESULTS: Overall, 17 women were identified suitable for this study. A total of 117 mature oocytes were vitrified for fertility preservation and 106 embryos were submitted to PGT-M. One patient returned to claim her cryopreserved oocytes, and five patients who underwent PGT-M embryo transfer reported three live births. A statistically significant decrease in selected fertility cycle parameters was observed in one woman who co-administered sorafenib (a multikinase inhibitor) during her first cycles of treatment, as the mean number of oocytes before and after was 2.7 (±1.3) versus 13.2 (±3.3) (P = 0.02), the mean number of metaphase II oocytes was 2.2 (±2.1) versus 7.7 (±2.6) (P = 0.007), and the mean number of two-pronuclei oocytes was 0.5 (±1.1) versus 3.5 (±1.7) (P = 0.09). Three patients had a median desmoid tumour growth on magnetic resonance imaging of 6.2 (2.9-7.2) cm when compared with prior ovarian stimulation imaging. CONCLUSIONS: Ovarian stimulation for women with desmoid tumours was characterized in some patients with an acceleration in tumour growth, regardless of the use of aromatase inhibitors. The use of sorafenib should be carefully considered during the course of fertility treatment.

Heterozygous APC germline mutations impart predisposition to colorectal cancer.

Familial adenomatous polyposis (FAP) is an inherited syndrome caused by a heterozygous adenomatous polyposis coli (APC) germline mutation, associated with a profound lifetime risk for colorectal cancer. While it is well accepted that tumorigenic transformation is initiated following acquisition of a second mutation and loss of function of the APC gene, the role of heterozygous APC mutation in this process is yet to be discovered. This work aimed to explore whether a heterozygous APC mutation induces molecular defects underlying tumorigenic transformation and how different APC germline mutations predict disease severity. Three FAP-human embryonic stem cell lines (FAP1/2/3-hESC lines) carrying germline mutations at different locations of the APC gene, and two control hESC lines free of the APC mutation, were differentiated into colon organoids and analyzed by immunohistochemistry and RNA sequencing. In addition, data regarding the genotype and clinical phenotype of the embryo donor parents were collected from medical records. FAP-hESCs carrying a complete loss-of-function of a single APC allele (FAP3) generated complex and molecularly mature colon organoids, which were similar to controls. In contrast, FAP-hESCs carrying APC truncation mutations (FAP1 and FAP2) generated only few cyst-like structures and cell aggregates of various shape, occasionally with luminal parts, which aligned with their failure to upregulate critical differentiation genes early in the process, as shown by RNA sequencing. Abnormal disease phenotype was shown also in non-pathological colon of FAP patients by the randomly distribution of proliferating cells throughout the crypts, compared to their focused localization in the lower part of the crypt in healthy/non-FAP patients. Genotype/phenotype analysis revealed correlations between the colon organoid maturation potential and FAP severity in the carrier parents. In conclusion, this study suggest that a single truncated APC allele is sufficient to initiate early molecular tumorigenic activity. In addition, the results hint that patient-specific hESC-derived colon organoids can probably predict disease severity among FAP patients.

Time-lapse imaging reveals delayed development of embryos carrying unbalanced chromosomal translocations.

PURPOSE: The purpose of the study was to compare the morphokinetic parameters of embryos carrying balanced chromosomal translocations with those carrying unbalanced chromosomal translocations using time-lapse microscopy. METHODS: The study group included 270 embryos that underwent biopsies on day 3 for preimplantation genetic diagnosis (PGD) for chromosomal translocations in our unit between 2013 and 2015. All embryos were incubated under time-lapse microscopy and evaluated for timing of developmental events up to day 5. The timing of these events was compared between balanced and unbalanced embryos, potentially viable and nonviable variants, and maternal versus paternal inheritance of the translocation. RESULTS: The PGD analysis found that 209 (77%) of the 270 biopsied embryos carried an unbalanced translocation. Embryos carrying unbalanced translocations, which are expected to lead to implantation failure or miscarriage, cleaved less synchronously and were delayed in time of cleavage to the 4-cell stage (t4) and in time of start of blastulation (tSB) compared with balanced embryos (P < 0.05). Furthermore, embryos carrying nonviable translocations demonstrated a significant delay at the time of pronuclei fading (tPNf) compared with those carrying potentially viable translocations (P < 0.05). Embryos whose unbalanced translocations were of maternal origin were significantly delayed in most of the morphokinetic parameters (including tPNf, t2, t3, t4, t6, t7, t8, cc2, s2, and tSB) compared with embryos carrying balanced translocations (P < 0.05). CONCLUSIONS: Embryos carrying unbalanced chromosomal translocations mainly of maternal origin undergo delayed development and asynchronous cleavage that may lead to implantation failure or miscarriage.

Obstetric and neonatal outcomes of pregnancies conceived after preimplantation genetic diagnosis: cohort study and meta-analysis.

Preimplantation genetic diagnosis (PGD) may pose risks to pregnancy outcome owing to the invasiveness of the biopsy procedure. This study compares outcome of singleton and twin clinical pregnancies conceived after fresh embryo transfers of PGD (n = 89) and matched intracytoplasmic sperm injection (ICSI) pregnancies (n = 166). The study was carried out in a single university affiliated centre. Because of the paucity of available data, a literature-based meta-analysis of studies comparing neonatal outcome of PGD and ICSI pregnancies was also conducted. In the retrospective cohort study, obstetric and neonatal outcome were available in 67 PGD and 118 ICSI pregnancies. Perinatal outcomes were comparable between PGD and ICSI pregnancies. Meta-analysis revealed similar outcomes, except for higher rate of low birth weight (<2500 g) neonates in ICSI twin pregnancies (RR 0.86, 95% CI 0.74 to 1.0). Mean birth weight, gestational age at birth, pre-term deliveries (<37 weeks) and malformations were all comparable. In this cohort study and subsequent meta-analysis, no association was found between PGD conceived pregnancies and risks of adverse neonatal or obstetrical outcomes compared with ICSI pregnancies. Hence, blastomere biopsy for PGD does not seem to increase the risk for adverse perinatal outcome compared with ICSI pregnancies.

Complex chromosomal rearrangement-a lesson learned from PGS.

PURPOSE: The aim of the study is to report a case of non-diagnosed complex chromosomal rearrangement (CCR) identified by preimplantation genetic screening (PGS) followed by preimplantation genetic diagnosis (PGD) which resulted in a pregnancy and delivery of healthy offspring. METHODS: A 29-year-old woman and her spouse, both diagnosed previously with normal karyotypes, approached our IVF-PGD center following eight early spontaneous miscarriages. PGS using chromosomal microarray analysis (CMA) was performed on biopsied trophectoderm. Fluorescence in situ hybridization (FISH), as well as re-karyotype, were performed on metaphase derived from peripheral blood of the couple. Subsequently, in the following PGD cycle, a total of seven blastocysts underwent CMA. RESULTS: A gain or loss at three chromosomes (3, 7, 9) was identified in six out of seven embryos in the first PGS-CMA cycle. FISH analysis of parental peripheral blood samples demonstrated that the male is a carrier of a CCR involving those chromosomes; this was in spite of a former diagnosis of normal karyotypes for both parents. Re-karyotype verified the complex translocation of 46,XY,t (3;7;9)(q23;q22;q22). Subsequently, in the following cycle, a total of seven blastocysts underwent PGD-CMA for the identified complex translocation. Two embryos were diagnosed with balanced chromosomal constitution. A single balanced embryo was transferred and pregnancy was achieved, resulting in the birth of a healthy female baby. CONCLUSIONS: PGS employing CMA is an efficient method to detect unrevealed chromosomal abnormalities, including complicated cases of CCR. The combined application of array CGH and FISH technologies enables the identification of an increased number of CCR carriers for which PGD is particularly beneficial.

The ovarian response in fragile X patients and premutation carriers undergoing IVF-PGD: reappraisal.

STUDY QUESTION: What is the association between the ovarian response and the number of CGG repeats among full mutation and premutation carriers of fragile X (FMR1), undergoing controlled ovarian hyperstimulation (COH) for PGD? SUMMARY ANSWER: Ovarian response was normal in full mutation patients but decreased in premutation carriers, although the number of repeats was not statistically significantly associated with the number of oocytes retrieved. WHAT IS KNOWN ALREADY: There is inconsistent data in the literature regarding ovarian response in FMR1 carriers. Studies exploring the ovarian response of full mutation patients are lacking. STUDY DESIGN, SIZE, DURATION: Retrospective study, a university affiliated tertiary hospital, IVF unit, PGD referral center. PARTICIPANTS/MATERIALS, SETTING, METHODS: We examined the medical records of all women undergoing fresh IVF-PGD cycles due to fragile X. Data recorded included demography, duration of stimulation, amount of gonadotropins administered, number of dominant follicles, maximal E2 levels and number of oocytes retrieved. Data were analyzed using univariate and multivariate mixed models. P-values <0.05 were considered significant. Data were collected from the medical records of 21 patients with a full mutation on the FMR1 gene and 51 premutation carriers. Overall 309 fresh cycles were analyzed. MAIN RESULTS AND THE ROLE OF CHANCE: Premutation carriers displayed reduced ovarian response, as demonstrated by fewer oocytes retrieved. In contrast, full mutation patients had a normal response. Comparison of premutation carriers and full mutation patients showed: mean oocytes retrieved per cycle (8.4 ± 1.1 versus 14.1 ± 1.7, P = 0.005), lower levels of estradiol (E2; 1756 ± 177, versus 2928 ± 263, P = 0.0004), respectively. There was no significant difference between premutation carriers and full mutation patients in regard to fertilization rate, cleavage rate or biopsy rate. No correlation was found between the number of repeats in the premutation carriers and the number of oocytes retrieved or E2 levels. Age and the type of protocol were the only factors found to be in correlation with the number of the oocyte retrieved (P = 0.037, and P = 0.003, respectively) among the premutation carriers. Similarly, no association was found between the number of repeats and the fertilization rate, cleavage rate or biopsy rate among premutation carriers. LIMITATIONS, REASONS FOR CAUTION: We had a relatively low number of premutation carriers with >100 repeats, which made it challenging to draw a firm conclusions from this group. WIDER IMPLICATIONS OF THE FINDINGS: Physicians must address the increased risk for reduced ovarian response and  primary ovarian insufficiency (POI) among carriers and consider surveillance of ovarian reserve markers. The last, might expedite family plans completion or fertility preservation. STUDY FUNDING/COMPETING INTEREST(S): None.

Improving preimplantation genetic diagnosis (PGD) reliability by selection of sperm donor with the most informative haplotype.

BACKGROUND: The study is aimed to describe a novel strategy that increases the accuracy and reliability of PGD in patients using sperm donation by pre-selecting the donor whose haplotype does not overlap the carrier's one. METHODS: A panel of 4-9 informative polymorphic markers, flanking the mutation in carriers of autosomal dominant/X-linked disorders, was tested in DNA of sperm donors before PGD. Whenever the lengths of donors' repeats overlapped those of the women, additional donors' DNA samples were analyzed. The donor that demonstrated the minimal overlapping with the patient was selected for IVF. RESULTS: In 8 out of 17 carriers the markers of the initially chosen donors overlapped the patients' alleles and 2-8 additional sperm donors for each patient were haplotyped. The selection of additional sperm donors increased the number of informative markers and reduced misdiagnosis risk from 6.00% ± 7.48 to 0.48% ±0.68. The PGD results were confirmed and no misdiagnosis was detected. CONCLUSIONS: Our study demonstrates that pre-selecting a sperm donor whose haplotype has minimal overlapping with the female's haplotype, is critical for reducing the misdiagnosis risk and ensuring a reliable PGD. This strategy may contribute to prevent the transmission of affected IVF-PGD embryos using a simple and economical procedure. TRIAL REGISTRATION: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. DNA testing of donors was approved by the institutional Helsinki committee (registration number 319-08TLV, 2008). The present study was approved by the institutional Helsinki committee (registration number 0385-13TLV, 2013).

The effect of a germline mutation in the APC gene on ß-catenin in human embryonic stem cells.

BACKGROUND: Most cases of colorectal cancer (CRC) are initiated by inactivation mutations in the APC gene, which is a negative regulator of the Wnt-ß-catenin pathway. Patients with familial adenomatous polyposis (FAP) inherit a germline mutation in one APC allele, and loss of the second allele leads to the development of polyps that will turn malignant if not removed. It is not fully understood which molecular mechanisms are activated by APC loss and when the loss of the second APC allele occurs. METHODS: Two FAP human embryonic stem cell (hESCs) lines were derived from APC mutated embryos following pre-implantation genetic diagnosis (PGD) for FAP. These FAP-hESCs were cultured in vitro and following extended culture: 1) ß-catenin expression was analyzed by Western blot analysis; 2) Wnt-ß-catenin/TCF-mediated transcription luciferase assay was performed; 3) cellular localization of ß-catenin was evaluated by immunoflorecence confocal microscopy; and 4) DNA sequencing of the APC gene was performed. RESULTS: We have established a novel human in-vitro model for studying malignant transformation, using hESCs that carry a germline mutation in the APC gene following PGD for FAP. Extended culturing of FAP1 hESCs led to activation of the Wnt signaling pathway, as demonstrated by enhanced ß-catenin/TCF-mediated activity. Additionally, ß-catenin showed a distinct perinuclear distribution in most (91 %) of the FAP1 hESCs high passage colonies. DNA sequencing of the whole gene detected several polymorphisms in FAP1 hESCs, however, no somatic mutations were discovered in the APC gene. On the other hand, no changes in ß-catenin were detected in the FAP2 hESCs, demonstrating the natural diversity of the human FAP population. CONCLUSIONS: Our results describe the establishment of novel hESC lines from FAP patients with a predisposition for cancer mutation. These cells can be maintained in culture for long periods of time and may serve as a platform for studying the initial molecular and cellular changes that occur during early stages of malignant transformation.

Blastomere biopsy for PGD delays embryo compaction and blastulation: a time-lapse microscopic analysis.

PURPOSE: The purpose of the study was to explore the effect of blastomere biopsy for preimplantation genetic diagnosis (PGD) on the embryos' dynamics, further cleavage, development, and implantation. METHODS: The study group included 366 embryos from all PGD treatments (September 2012 to June 2014) cultured in the EmbryoScope™ time-lapse monitoring system. The control group included all intracytoplasmic sperm injection (ICSI) embryos cultured in EmbryoScope™ until day 5 during the same time period (385 embryos). Time points of key embryonic events were analyzed with an EmbryoViewer™. RESULTS: Most (88 %) of the embryos were biopsied at ≥8 cells. These results summarize the further dynamic development of the largest cohort of biopsied embryos and demonstrate that blastomere biopsy of cleavage-stage embryos significantly delayed compaction and blastulation compared to the control non-biopsied embryos. This delay in preimplanation developmental events also affected postimplantation development as observed when the dynamics of non-implanted embryos (known implantation data (KID) negative) were compared to those of implanted embryos (KID positive). CONCLUSION: Analysis of morphokinetic parameters enabled us to explore how blastomere biopsy interferes with the dynamic sequence of developmental events. Our results show that biopsy delays the compaction and the blastulation of the embryos, leading to a decrease in implantation.

Genomic analysis of hESC pedigrees identifies de novo mutations and enables determination of the timing and origin of mutational events.

Given the association between mutational load and cancer, the observation that genetic aberrations are frequently found in human pluripotent stem cells (hPSCs) is of concern. Prior studies in human induced pluripotent stem cells (hiPSCs) have shown that deletions and regions of loss of heterozygosity (LOH) tend to arise during reprogramming and early culture, whereas duplications more frequently occur during long-term culture. For the corresponding experiments in human embryonic stem cells (hESCs), we studied two sets of hESC lines: one including the corresponding parental DNA and the other generated from single blastomeres from four sibling embryos. Here, we show that genetic aberrations observed in hESCs can originate during preimplantation embryo development and/or early derivation. These early aberrations are mainly deletions and LOH, whereas aberrations arising during long-term culture of hESCs are more frequently duplications. Our results highlight the importance of close monitoring of genomic integrity and the development of improved methods for derivation and culture of hPSCs.

Mutated human embryonic stem cells for the study of human genetic disorders.

Human embryonic stem cells (HESCs) are of great interest in biology and medicine due to their ability to grow indefinitely in culture while maintaining their ability to differentiate into all different cell types in the human body. In addition, HESCs can be used for better understanding the key developmental processes and can, therefore, serve for studying genetic disorders for which no good research model exists. Preimplantation genetic diagnosis of in vitro derived embryos results in affected-spare blastocysts with specific known inherited mutations.These affected blastocysts can be used for the derivation of disease-bearing HESCs, which would serve for studying the molecular and pathophysiological mechanisms underlying the genetic disease for which they were diagnosed. This chapter describes the methods to derive HESCs carrying mutations for inherited disorders.

Effects of laser polar-body biopsy on embryo quality.

OBJECTIVE: To evaluate the effect of laser polar-body biopsy (PBB) for preimplantation genetic diagnosis on embryo quality. STUDY DESIGN: Retrospective case-control analysis. The quality of 145 embryos after PBB was compared to 276 embryos of the same group of women without biopsy. SETTING: University-based tertiary-care medical center. PATIENT(S): Women with inherited genetics disease. INTERVENTION(S): Laser PBB of IVF embryos for genetic diagnosis. MAIN OUTCOME MEASURE(S): The study and control embryos were compared for fertilization rate, pronuclear grading, and cleavage-stage parameters on days 1, 2, and 3 after oocyte retrieval. RESULT(S): The study embryos demonstrated higher rates of cleavage arrest (3.6% vs. 0.7%), higher rate of significant fragmentation on day 2 (9.5% vs. 3.0%), and lower rate of good cleavage embryos on day 2 (69.1% vs. 78.4%) compared with control embryos. On day 3, the study embryos had lower cleavage rates (six or more blastomeres; 56.5% vs. 74.5%), higher fragmentation (11.7% vs. 3.9%), higher rate of embryos presenting inferior cleavage pattern (57.2% vs. 38.5%), and lower mean blastomere number (5.8 ± 2.1 vs. 6.6 ± 1.9) compared with control embryos. CONCLUSION(S): Polar-body biopsy may have a negative effect on embryo quality.

Female sex bias in human embryonic stem cell lines.

The factors limiting the rather inefficient derivation of human embryonic stem cells (HESCs) are not fully understood. The aim of this study was to analyze the sex ratio in our 42 preimplantation genetic diagnosis (PGD)-HESC lines, in an attempt to verify its affect on the establishment of HESC lines. The ratio between male and female PGD-derived cell lines was compared. We found a significant increase in female cell lines (76%). This finding was further confirmed by a meta-analysis for combining the results of all PGD-derived HESC lines published to date (148) and all normal karyotyped HESC lines derived from spare in vitro fertilization embryos worldwide (397). Further, gender determination of embryos demonstrated that this difference originates from the actual derivation process rather than from unequal representation of male and female embryos. It can therefore be concluded that the clear-cut tendency for female preponderance is attributed to suboptimal culture conditions rather than from a true gender imbalance in embryos used for derivation of HESC lines. We propose a mechanism in which aberrant X chromosome inactivation and/or overexpression of critical metabolic X-linked genes might explain this sex dimorphism.