Faculty Bibliography

Pre-implantation genetic diagnosis (PGD) has changed the landscape of clinical genetics by helping families reduce the transmission of monogenic disorders. However, given the high prevalence of embryonic aneuploidy, particularly in patients of advanced reproductive age, unaffected embryos remain at high risk of implantation failure or pregnancy loss due to aneuploidy. 24-chromosome aneuploidy screening has become widely utilized in routine in vitro fertilization (IVF) to pre-select embryos with greater pregnancy potential, but concurrent 24-chromosome aneuploidy screening has not become standard practice in embryos biopsied for PGD. We performed a retrospective cohort study of patients who underwent PGD with or without 24-chromosome aneuploidy screening to explore the value of concurrent screening. Among the PGD + aneuploidy-screened group (n = 355 blastocysts), only 25.6 % of embryos were both Single Gene Disorder (SGD)-negative (or carriers) and euploid; thus the majority of embryos were ineligible for transfer due to the high prevalence of aneuploidy. Despite a young mean age (32.4 +/- 5.9y), 49.9 % of Blastocysts were aneuploid. The majority of patients (53.2 %) had >/=1 blastocyst that was Single Gene Disorder (SGD)-unaffected but aneuploid; without screening, these unaffected but aneuploid embryos would likely have been transferred resulting in implantation failure, pregnancy loss, or a pregnancy affected by chromosomal aneuploidy. Despite the transfer of nearly half the number of embryos in the aneuploidy-screened group (1.1 +/- 0.3 vs. 1.9 +/- 0.6, p < 0.0001), the implantation rate was higher (75 % vs. 53.3 %) and miscarriage rate lower (20 % vs. 40 %) (although not statistically significant). 24-chromosome aneuploidy screening when performed concurrently with PGD provides valuable information for embryo selection, and notably improves single embryo transfer rates.

PURPOSE: The purpose of our study was to determine if progesterone (P4) values on day of trigger affect certain cycle outcome parameters, ploidy status of embryos, as well as pregnancy outcomes in the subsequent first frozen embryo transfer cycle. METHODS: Two hundred thirty-eight patients undergoing pre-gestational screening and freeze all protocol at our fertility center from 2013 to 2014 were included. Excluded patients were those whom had cancelled cycles prior to egg retrieval as well as cycles utilizing donor eggs. Once patients were identified as eligible for this study, frozen serum from the day of trigger was identified and analyzed using the Siemens Immulite 2000. Number of eggs retrieved, number of available embryos for biopsy, and number of euploid/aneuploid embryos were analyzed. The first frozen embryo transfer cycle was linked to the initial egg retrieval and outcomes including pregnancy rates, and live birth/ongoing pregnancy rates were calculated and analyzed. A discriminatory P4 value of 1.5 ng/ml was set. Group A had P4 values of less than 1.5 ng/ml and group B had P4 values greater than or equal to 1.5 ng/ml. T tests and chi-squared tests were used for statistical analysis. RESULTS: Group A had an average trigger P4 value of 0.87 +/- 0.3 and group B had an average trigger P4 of 2.1 +/- 0.8. Table 1 shows the baseline characteristics of both group A and group B. The only significant difference between the two groups was total gonadotropin dosage (IU) with a p value of 0.02 and estradiol (pg/ml) at trigger, also with a p value of 0.02 (Table 1). Number of eggs retrieved, number of embryos biopsied, number euploid/aneuploid, and non-diagnosis embryos were all non-significant. Chi-square analysis was used to compare pregnancy rates between the two groups after the first frozen embryo transfer cycle. Group A had a pregnancy rate of 72 % and Group B had a pregnancy rate of 66.7 %, which was not significant. Ongoing pregnancy/live birth rates were 65.6 % in group A and 66.67 % in group B, also not significant (Table 2). CONCLUSIONS: P4 values on day of trigger do not affect number of eggs retrieved and number of chromosomally normal embryos available for transfer in a subsequent embryo transfer cycle. Elevated P4 values (>/=1.5 ng/ml) also do not affect pregnancy rates or live birth/ongoing pregnancy rates in the first subsequent frozen embryo transfer cycle.

STUDY HYPOTHESIS: We wanted to probe the opinions and current practices on preimplantation genetic screening (PGS), and more specifically on PGS in its newest form: PGS 2.0. STUDY FINDING: Consensus is lacking on which patient groups, if any at all, can benefit from PGS 2.0 and, a fortiori, whether all IVF patients should be offered PGS. WHAT IS KNOWN ALREADY: It is clear from all experts that PGS 2.0 can be defined as biopsy at the blastocyst stage followed by comprehensive chromosome screening and possibly combined with vitrification. Most agree that mosaicism is less of an issue at the blastocyst stage than at the cleavage stage but whether mosaicism is no issue at all at the blastocyst stage is currently called into question. STUDY DESIGN, SAMPLES/MATERIALS, METHODS: A questionnaire was developed on the three major aspects of PGS 2.0: the Why, with general questions such as PGS 2.0 indications; the How, specifically on genetic analysis methods; the When, on the ideal method and timing of embryo biopsy. Thirty-five colleagues have been selected to address these questions on the basis of their experience with PGS, and demonstrated by peer-reviewed publications, presentations at meetings and participation in the discussion. The first group of experts who were asked about "The Why" comprised fertility experts, the second group of molecular biologists were asked about "The How" and the third group of embryologists were asked about "The When". Furthermore, the geographical distribution of the experts has been taken into account. Thirty have filled in the questionnaire as well as actively participated in the redaction of the current paper. MAIN RESULTS AND THE ROLE OF CHANCE: The 30 participants were from Europe (Belgium, Germany, Greece, Italy, Netherlands, Spain, UK) and the USA. Array comparative genome hybridization is the most widely used method amongst the participants, but it is slowly being replaced by massive parallel sequencing. Most participants offering PGS 2.0 to their patients prefer blastocyst biopsy. The high efficiency of vitrification of blastocysts has added a layer of complexity to the discussion, and it is not clear whether PGS in combination with vitrification, PGS alone, or vitrification alone, followed by serial thawing and eSET will be the favoured approach. The opinions range from in favour of the introduction of PGS 2.0 for all IVF patients, over the proposal to use PGS as a tool to rank embryos according to their implantation potential, to scepticism towards PGS pending a positive outcome of robust, reliable and large-scale RCTs in distinct patient groups. LIMITATIONS, REASONS FOR CAUTION: Care was taken to obtain a wide spectrum of views from carefully chosen experts. However, not all invited experts agreed to participate, which explains a lack of geographical coverage in some areas, for example China. This paper is a collation of current practices and opinions, and it was outside the scope of this study to bring a scientific, once-and-for-all solution to the ongoing debate. WIDER IMPLICATIONS OF THE FINDINGS: This paper is unique in that it brings together opinions on PGS 2.0 from all different perspectives and gives an overview of currently applied technologies as well as potential future developments. It will be a useful reference for fertility specialists with an expertise outside reproductive genetics.Large scale data: none. STUDY FUNDING AND COMPETING INTERESTS: No specific funding was obtained to conduct this questionnaire.

INTRODUCTION: PI3K/AKT/mTOR up-regulation results in accelerated activation of the primordial follicle (PMF) pool and has been implicated in cyclophosphamide (CY)-induced 'follicular exhaustion'. We compared follicular dynamics in murine models of CY-induced POI and age-related DOR, hypothesizing that 'follicular exhaustion' may occur similarly in both groups. METHODS: C57BL/6 female mice aged 8 wks (n=25) housed in identical conditions were assigned to 5 groups: 150mg/kg CY intraperitoneal (IP) x1, 75mg/kg CY IP weekly x3, control (8 wks and 11 wks), and DOR (13 months). Blood was extracted by terminal cardiac puncture for anti-mullerian hormone (AMH). Ovaries were paraffin-embedded, sectioned, and H&E stained; blinded follicle counts were confirmed by two reviewers. Follicle counts are presented as follicles/section area (mm2); data presented as mean+/-SEM. One-way ANOVA and student's t-test were used for statistical analysis (p<0.05). 'Follicular exhaustion' was calculated as the ratio of total growing follicles (primary, secondary, antral) to PMFs. RESULTS: A DOR murine model was confirmed by low AMH in 13-mth-old mice compared to controls (7.2+/-0.1 vs. 12.1+/-0.5, p<0.05) and fewer PMFs/mm2 (0.6+/-0.2) compared to 8-wk (7.7+/-1.2) and 11 wk controls (6.0+/-1) (p<0.05). A CY-induced POI model was confirmed by lower AMH in 150mg/kg CY-exposed mice compared to age-matched controls (9.6+/-0.9 vs. 12.1+/-0.5) and fewer PMFs/mm2 (2.5+/-0.4 vs. 7.7+/-1.2, p<0.05). CY-treated mice had more primary & secondary follicles/mm2 compared to controls (p<0.05), suggesting increased follicle activation. PMF counts were similar in POI [75mg/kg CY (2.4 +/- 0.5) and 150mg/ kg CY (1.9+/-0.3)] compared to DOR (0.6+/-0.2) despite an 11-mth age difference. Importantly, similar rates of 'follicular exhaustion' were seen in CY-exposed POI mice (75mg/kg CY ratio 1.9; 150mg/kg CY ratio 2.6) and DOR mice (ratio 2.4). In contrast, low 'follicular exhaustion' ratios were seen in both control groups (8-wks ratio 0.64; 11-wks ratio 0.89) signifying maintenance of follicles as PMFs. CONCLUSIONS: Accelerated PMF activation and subsequent follicular exhaustion occur similarly in murine models of CY-induced POI and age-related DOR. Future studies should investigate if PI3K/AKT/mTOR up-regulation is also involved in DOR, suggesting possible implications for prevention

PURPOSE: Preimplantation genetic screening (PGS) and diagnosis (PGD) with euploid embryo transfer is associated with improved implantation and live birth rates as compared to routine in vitro fertilization. However, misdiagnosis of the embryo is a potential risk. The purpose of this study was to investigate the clinical discrepant diagnosis rate associated with transfer of trophectoderm-biopsied blastocysts deemed to be euploid via array comparative genomic hybridization (aCGH). METHODS: This is a retrospective cohort study including cycles utilizing PGS or PGD with trophectoderm biopsy, aCGH, and euploid embryo transfer at a large university-based fertility center with known birth outcomes from November 2010 through July 2014 (n = 520). RESULTS: There were 520 embryo transfers of 579 euploid embryos as designated by aCGH. Five discrepant diagnoses were identified. Error rate per embryo transfer cycle was 1.0 %, 0.9 % per embryo transferred, and 1.5 % per pregnancy with a sac. The live birth (LB) error rate was 0.7 % (both sex chromosome errors), and the spontaneous abortion (SAB) error rate was 17.6 % (3/17 products of conception tested, but could range from 3/42 to 7/42). No single gene disorders were mistakenly selected for in any known cases. CONCLUSIONS: Although aCGH has been shown to be a highly sensitive method of comprehensive chromosome screening, several possible sources of error still exist. While the overall error rate is low, these findings have implications for counseling couples that are contemplating PGS and PGD with aCGH.