Preimplantation Genetic Diagnosis For Aneuploidy Research Articles

P–521 Association between maternal age and euploid blastocyst availability in cycles with less than four two-pronucleate zygotes

Abstract Study question For patients with less than four two-pronucleate (2pn) zygotes, is there an age-cutoff above which preimplantation genetic diagnosis for aneuploidy (PGT-A) is futile? Summary answer Women over 40y with less than four 2pn zygotes should consider transfer of a day 3 embryo over culture to blastocyst with PGT-A. What is known already During a typical IVF cycle, there is unavoidable attrition from oocytes retrieved, to embryos obtained, to blastocysts formed such that some patients, particularly those with advanced age or poor ovarian response, may not have blastocysts available to biopsy. While randomized trials have shown improved pregnancy rates with the use of PGT-A in patients of advancing age, these trials primarily included patients with good ovarian reserve and multiple blastocysts available. The optimal age group within poor responders who would benefit most from PGT-A has yet to be determined. Study design, size, duration This was a retrospective cohort study of all fresh autologous IVF or IVF/ICSI cycles in which PGT-A was planned from 1/2012 to 3/2020. Only patients with less than four 2pn zygotes were included. A total of 85 cycles from 75 patients were analyzed. Participants/materials, setting, methods Number of cleavage-stage embryos, blastocysts, biopsy-quality blastocysts and euploid embryos were assessed, after stratification by age. Adjusted relative risks (aRR) and 95% confidence intervals (CI) were calculated adjusting for BMI, AMH, FSH, stimulation protocol, and ICSI. Poisson regression was used for counts. Generalized estimating equations were used to account for patients contributing multiple cycles. Main results and the role of chance There were no differences in number of 2pn zygotes (p = 0.98) or cleavage stage embryos (p = 0.94) across age groups. Patients aged 41–42y had a significantly lower number of blastocysts (1.18 vs. 2.00; aRR 0.59 95%CI: 0.37–0.95) and biopsy-quality blastocysts (0.73 vs. 1.53; aRR 0.50 95% CI: 0.26–0.98) compared to patients <35y.These patients also had fewer euploid embryos available (0.09 vs 0.67), although the difference was not significant in the adjusted model (aRR 0.14 95% CI: 0.01–1.57). None of the patients >42y had euploid blastocysts. When considering the mean and three standard deviations (0.09 [SD 0.3]), 99.7% of patients over 40y have no euploid embryo available for transfer. Limitations, reasons for caution This study was retrospective in nature and limited by small sample sizes when patients were stratified by age. A prospective randomized trial of patients with less than four 2pn zygotes to day 3 fresh embryo transfer vs PGT-A frozen embryo transfer is needed to confirm these findings. Wider implications of the findings: Patients over 40y with less than four 2pn zygotes are at high risk of having no euploid blastocysts. While the literature demonstrates higher live birth rates with the use of PGT-A in women of advancing age, this is inconsequential if there is no embryo available to transfer. Trial registration number Not applicable

P–615 The effect of late-follicular phase progesterone rise on embryo ploidy, embryo quality and cumulative live birth rates following a freeze-only strategy

Abstract Study question Is late-follicular phase progesterone elevation (PE) associated with a deleterious effect on embryo euploidy, embryo blastulation and cumulative live birth rates (CLBRs)? Summary answer Late-follicular phase PE has no impact on impact on embryo euploidy rate, embryo blastulation rate nor on the CLBR. What is known already The effect of PE in ART outcomes has been extensively studied, yielding so far conflicting results. While some authors claim it is only detrimental to endometrial receptivity, others have suggested that it may also impair oocyte/embryo quality. Moreover, little is known regarding the potential effect PE may have on embryo ploidy and, consequently, CLBR. Study design, size, duration A multicenter retrospective cross-sectional study was performed between August 2017 and December 2019. A total of 1495 ICSI cycles coupled with preimplantation genetic diagnosis for aneuploidies (PGT-A) and deferred frozen embryo transfer (FET) were analyzed. Participants/materials, setting, methods All patients underwent ovarian stimulation with GnRH antagonist protocol and performed a serum progesterone measurement at one of the participating private fertility clinics on the day of trigger. The sample was stratified according to the progesterone levels: normal (≤1.50 ng/ml) and high (>1.50 ng/ml). The primary outcome was the embryo euploidy rate. Secondary outcomes were the number of euploid blastocysts, the blastulation rate and CLBR. Main results and the role of chance Late-follicular phase PE was associated with higher late-follicular estradiol levels (2847.56±1091.10 pg/ml vs. 2240.94± 996.37 pg/ml, p < 0.001) and more oocytes retrieved (17.67±8.86 vs. 12.70±7.00, p < 0.001). The number of euploid embryos was higher in the PE group (2.32±1.74 vs. 1.86±1.42, p < 0.001), whereas the embryo euploidy rate (48.3% [44.9%–51.7%] vs. 49.1% [47.7%–50.6%] and blastulation rate (47.1% [43.7%–50.5%] vs. 51.0% [49.7%–52.4%]) were comparable between the two groups. Likewise, no significant differences were found regarding the live birth rate (LBR) after the first FET (34.1% vs. 31.1%, p = 0.427) nor the CLBRs (38.9% vs. 37.0%, p = 0.637). Mixed-model analysis was performed in order to account for the clustering of cycles in the same patient. Adjusting for patients’ age, PE and BMI, PE failed to demonstrate any effect on the embryo euploidy rate (OR 1.03 [95% CI 0.89–1.20]). Mixed-model analysis for the number of euploid embryos was also performed. After adjusting for PE, age, BMI and ovarian response, PE did not affect the number of euploid embryos (0.02 [95%CI –0.21;0.25]. Multivariate logistic regression adjusted for PE, age, BMI and ovarian response revealed that PE was not associated with the CLBR (adjOR 0.96 [95% CI 0.66–1.38]). Limitations, reasons for caution Limitations of the study include its retrospective nature. Moreover, including only GnRH antagonist protocol and ICSI does not allow the extrapolation of these results to other populations. Wider implications of the findings: Our findings question results from previous studies claiming a detrimental effect of PE on embryo implantation potential. According to our results, PE has no impact on embryo euploidy rate, blastulation rate nor on CLBRs. Trial registration number Not applicable

PGT-A and RCT proof in AMA and SMF couples

Aneuploidy is the most common genetic abnormality in human embryos. Preimplantation genetic diagnosis for aneuploidy (PGT-A) can increase pregnancy rates in infertile couples requiring assisted reproductive technology (ART). Large datasets from testing preimplantation embryos demonstrate that over half of embryos produced by in vitro fertilization (IVF) are aneuploid. Conventional embryo morphology evaluation as well as morphokinetics can not properly discriminate euploid from aneuploid embryos. Particularly, trisomic embryos that behave very similarly to euploid embryos. For these reasons, PGT-A started to be applied for several indications. In the present talk the results of two randomized trials (RCTs) in advanced maternal age (AMA) and severe male factor (SMF) will be discussed. In both studies, livebirths/ongoing pregnancy rates were compared among patients with blastocyst transfer as a control group and a study group in which day-3 biopsy was performed, and array CGH was applied for 24-chromosome analysis, with the transfer of euploid blastocysts. The final results of the AMA study conducted in women between 38 and 41 years of age included a total of 205 cycles. The PGT-A group exhibited significantly fewer embryo transfers (68.0%, vs. 90.5% for control; p=0.0001), and lower miscarriage rates (2.7%, vs. 39.0% for control; p=0.0007). Delivery rate after the first transfer attempt was significantly higher in the PGT-A group per transfer (52.9% vs. 24.2%; p=0.0002), and per patient (36.0% vs. 21.9%; p=0.0309). No significant differences were observed in the cumulative delivery rates per patient six months after closing the study. However, the mean number of embryo transfers needed per live birth was lower in the PGD-A group compared to control group (1.8 vs. 3.7), as was the time to pregnancy (7.7 vs. 14.9 weeks). The interim analysis of SMF study was performed when 101 cycles were completed and included women We can conclude that the benefits of testing embryos for common chromosomal abnormalities, include: increased ongoing implantation and pregnancy rates per transfer, decreased miscarriage rates per patient, and faster time to pregnancy when compared to conventional embryo scoring by morphology alone. Also, we concluded that PGT-A with the new approaches with throphectoderm biopsy and Next Generation Sequencing (NGS) the cost per treatment can decrease, being like a conventional cycle if we consider the endpoint of a healthy livebirth per cycle.

Assisted reproductive technology (ART) cumulative live birth rates following preimplantation genetic diagnosis for aneuploidy (PGD-A) or morphological assessment of embryos: A cohort analysis.

Preimplantation genetic diagnosis for aneuploidy (PGD-A) for all 24 chromosomes improves implantation and clinical pregnancy rates per single assisted reproductive technology (ART) cycle. However, there is limited data on the live-birth rate of PGD-A over repeated cycles. To assess the cumulative live-birth rates (CLBR) of PGD-A compared with morphological assessment of embryos of up to three 'complete ART cycles' (fresh plus frozen/thaw cycles) in women aged 37years or older. A retrospective cohort study of ART treatments undertaken by ART-naïve women at a large Australian fertility clinic between 2011 and 2014. Cohorts were assigned based on the embryo selection method used in their first fresh cycle [PGD-A, n=110 women (PGD-A group); morphological assessment of embryos, n=1983 women (control group)]. CLBR, time to clinical pregnancy and cycles needed to achieve a live birth were measured over multiple cycles. Compared to the control group, the PGD-A group achieved a higher per cycle live-birth rate (14.47% vs 9.12%, P<0.01), took a shorter mean time to reach a clinical pregnancy leading to a live-birth (104.8days vs 140.6days, P<0.05) and required fewer cycles to achieve a live-birth (6.91 cycles vs 10.96 cycles, P<0.01). However, after three 'complete ART cycles', the CLBR was comparable for the two groups (30.90% vs 26.77%, P=0.34). This is the first study to assess the effectiveness of PGD-A over multiple ART cycles. These real-world findings suggest that PGD-A leads to better outcomes than using morphological assessment alone in women of advanced maternal age.

In vitro fertilization with preimplantation genetic diagnosis for aneuploidies in advanced maternal age: a randomized, controlled study

To determine the clinical value of preimplantation genetic diagnosis for aneuploidy screening (PGD-A) in women of advanced maternal age (AMA; between 38 and 41years). This was a multicenter, randomized trial with two arms: a PGD-A group with blastocyst transfer, and a control group with blastocyst transfer without PGD-A. Private reproductive centers. A total of 326 recruited patients fit the inclusion criteria, and 205 completed the study (100 in the PGD-A group and 105 in the control group). Day-3 embryo biopsy, array comparative genomic hybridization, blastocyst transfer, and vitrification. Primary outcomes were delivery and live birth rates in the first transfer and cumulative outcome rates. The PGD-A group exhibited significantly fewer ETs (68.0% vs. 90.5% for control) and lower miscarriage rates (2.7% vs. 39.0% for control). Delivery rate after the first transfer attempt was significantly higher in the PGD-A group per transfer (52.9% vs 24.2%) and per patient (36.0% vs. 21.9%). No significant differences were observed in the cumulative delivery rates per patient 6months after closing the study. However, the mean number of ETs needed per live birth was lower in the PGD-A group compared with the control group (1.8 vs. 3.7), as was the time to pregnancy (7.7 vs. 14.9weeks). Preimplantation genetic diagnosis for aneuploidy screening is superior compared with controls not only in clinical outcome at the first ET but also in dramatically decreasing miscarriage rates and shortening the time to pregnancy.

Preimplantation genetic diagnosis for aneuploidy testing in women older than 44 years: a multicenter experience

To report laboratory and clinical outcomes in preimplantation genetic diagnosis for aneuploidies (PGD-A) cycles for women 44 to 47years old. Multicenter, longitudinal, observational study. Invitro fertilization (IVF) centers. One hundred and thirty-seven women aged 44.7 ± 0.7years (range: 44.0-46.7) undergoing 150 PGD-A cycles during April 2013 to January2016. Quantitative polymerase chain reaction-based PGD-A on trophectoderm biopsies and cryopreserved euploid single-embryo transfer (SET). Primary outcome measure: delivery rate per cycle; secondary outcome measures: miscarriage rate, and the rate and reasons for cycle cancelation with subanalyses for female age and number of metaphase 2 oocytes retrieved. In 102 (68.0%) of 150 cycles blastocyst development was obtained, but only 21 (14.0%) were euploid blastocysts. The overall euploidy rate was 11.8% (22 of 187). Twenty-one SET procedures were performed, resulting in 13 clinical pregnancies, of which 1 miscarried and 12 delivered. The delivery rate was 57.1% per transfer, 8.0% per cycle, and 8.8% per patient. The logistic regression analysis found that only female age (odds ratio 0.78) and number of metaphase 2 oocytes retrieved (odds ratio 1.25) statistically significantly correlated with the likelihood of delivery. The delivery rate per cycle was 10.6% (11 of 104) in patients aged 44.0 to 44.9years and 2.6% in patients aged 45.0 to 45.9years (n = 1 of 38). No euploid blastocysts were found for patients older than 45.0years. Extensive counseling based on biological and clinical data should be provided to women older than 43years who are requesting IVF because of their very low odds of success and high risk for embryonic aneuploidies. Nevertheless, the low miscarriage and good delivery rates reported in this study in women with good ovarian reserve aged 44 should encourage the use of PGD-A in this population.

The accumulation of vitrified oocytes is a strategy to increase the number of euploid available blastocysts for transfer after preimplantation genetic testing

PurposeIn a preimplantation genetic diagnosis for aneuploidy (PGD-A) program, the more embryos available for biopsy, consequently increases the chances of obtaining euploid embryos to transfer. The aim was to increase the number of viable euploid blastocysts in patients undergoing PGD-A using fresh oocytes together with previously accumulated vitrified oocytes.MethodsSixty-nine patients with normal ovarian reserve underwent PGD-A for repeated implantation failure or recurrent pregnancy loss indication. After several cycles of ovarian stimulation, 591 accumulated vitrified oocytes and 463 fresh oocytes were micro-injected with the same partner’s semen sample. PGD-A was completed on 134 blastocysts from vitrified/warmed oocytes and 130 blastocysts from fresh oocytes.ResultsA mean of 9.6% euploid blastocyst per micro-injected vitrified/warmed oocytes and 11.4% euploid blastocyst per micro-injected fresh oocyte were obtained (p > 0.05). The euploidy and aneuploidy rates were comparable in blastocysts obtained from micro-injected vitrified/warmed oocytes and fresh oocytes (42.5 versus 40.8% and 57.5 versus 59.2%, p > 0.05). Implantation rates of euploid blastocysts were comparable between the two sources of oocytes (56.0% from vitrified/warmed oocytes versus 60.9% from fresh oocytes, p > 0.05).ConclusionsOocyte vitrification and warming do not generate aneuploidy in blastocysts. The number of viable euploid embryos for transfer can be increased by using accumulated vitrified oocytes together with fresh oocytes in ICSI.Trial registrationNCT02820415 ClinicalTrials.gov

The effect of embryo selection by preimplantation genetic diagnosis for aneuploidy (PGD-A) in patients with advanced maternal age

The effect of embryo selection by preimplantation genetic diagnosis for aneuploidy (PGD-A) in patients with advanced maternal age

Commentary re: Causes and estimated incidences of sex-chromosome misdiagnosis in preimplantation genetic diagnosis of aneuploidy

Commentary re: Causes and estimated incidences of sex-chromosome misdiagnosis in preimplantation genetic diagnosis of aneuploidy

Causes and estimated incidences of sex-chromosome misdiagnosis in preimplantation genetic diagnosis of aneuploidy

Preimplantation genetic diagnosis of aneuploidy (PGD-A) with comprehensive chromosome analysis has been known to improve pregnancy outcomes. Accuracy in detecting sex chromosomes becomes important when selecting against embryos at risk for sex-linked disorders. A total of 21,356 PGD-A cycles consisting of day-3 (cleavage) or day-5 (blastocyst) biopsies were received at the same laboratory for PGD-A via fluorescence in situ hybridization (FISH) or array comparative genome hybridization (aCGH) from multiple fertility centres. The misdiagnosis rates were 0.12% (Wilson 95% CI 0.05 to 0.25%) in day-3 FISH cycles, 0.48% (Wilson 95% CI 0.19 to 1.22%) in day-3 aCGH cycles and 0.0% (Wilson 95% CI 0 to 0.26) in day-5 aCGH cycles. Although rare, the likely causative biological event for true misdiagnosis is embryonic XX/XY mosaicism. Reanalysis of 1219 abnormal cleavage-stage research embryos revealed a 73% incidence of minor and major mosaicism. Only four (0.3%) embryos were found to be diploid and contained XX and XY cells that could potentially account for the misdiagnosis of sex. Our investigation identified errors leading to misdiagnosis and their attribution to specific events during PGD-A testing. The reported misdiagnosis rates suggest that PGD-A for sex determination is highly accurate, particularly when using aCGH applied to blastocyst biopsies.

Preimplantation genetic testing for aneuploidy: what technology should you use and what are the differences?

The purpose of the review was to define the various diagnostic platforms currently available to perform preimplantation genetic testing for aneuploidy and describe in a clear and balanced manner the various strengths and weaknesses of these technologies. A systematic literature review was conducted. We used the terms "preimplantation genetic testing," "preimplantation genetic diagnosis," "preimplantation genetic screening," "preimplantation genetic diagnosis for aneuploidy," "PGD," "PGS," and "PGD-A" to search through PubMed, ScienceDirect, and Google Scholar from the year 2000 to April 2016. Bibliographies of articles were also searched for relevant studies. When possible, larger randomized controlled trials were used. However, for some emerging data, only data from meeting abstracts were available. PGS is emerging as one of the most valuable tools to enhance pregnancy success with assisted reproductive technologies. While all of the current diagnostic platforms currently available have various advantages and disadvantages, some platforms, such as next-generation sequencing (NGS), are capable of evaluating far more data points than has been previously possible. The emerging complexity of different technologies, especially with the utilization of more sophisticated tools such as NGS, requires an understanding by clinicians in order to request the best test for their patients.. Ultimately, the choice of which diagnostic platform is utilized should be individualized to the needs of both the clinic and the patient. Such a decision must incorporate the risk tolerance of both the patient and provider, fiscal considerations, and other factors such as the ability to counsel patients on their testing results and how these may or may not impact clinical outcomes.

Outcomes of in vitro fertilization with preimplantation genetic diagnosis: an analysis of the United States Assisted Reproductive Technology Surveillance Data, 2011–2012

To assess the characteristics of IVF cycles for which preimplantation genetic diagnosis (PGD) was used and to evaluate indications for PGD and treatment outcomes associated with this procedure as compared with cycles without PGD with the data from the U.S. National ART Surveillance System. Retrospective cohort study. None. Fresh autologous cycles that involved transfer of at least one embryo at blastocyst when available. None. PGD indications and age-specific reproductive outcomes. There were a total of 97,069 non-PGD cycles and 9,833 PGD cycles: 55.6% were performed for aneuploidy screening (PGD Aneuploidy), 29.1% for other reasons (PGD Other), and 15.3% for genetic testing (PGD Genetic). In comparison to non-PGD cycles, PGD Aneuploidy cycles showed a decreased odds of miscarriage among women 35-37 years (adjusted odds ratio [aOR] 0.62; 95% CI, 0.45-0.87) and women >37 years (aOR 0.55; 95% CI, 0.43-0.70); and an increased odds of clinical pregnancy (aOR 1.18; 95% CI, 1.05-1.34), live-birth delivery (aOR 1.43; 95% CI, 1.26-1.62), and multiple-birth delivery (aOR 1.98; 95% CI, 1.52-2.57) among women >37 years. Aneuploidy screening was the most common indication for PGD. Use of PGD was not observed to be associated with an increased odds of clinical pregnancy or live birth for women <35 years. PGD for aneuploidy was associated with a decreased odds of miscarriage for women >35 years, but an increased odds of a live-birth and a multiple live-birth delivery among women >37 years.

The clinical effectiveness of preimplantation genetic diagnosis for aneuploidy in all 24 chromosomes (PGD-A): systematic review.

Is preimplantation genetic diagnosis for aneuploidy (PGD-A) with analysis of all chromosomes during assisted reproductive technology (ART) clinically and cost effective? The majority of published studies comparing a strategy of PGD-A with morphologically assessed embryos have reported a higher implantation rate per embryo using PGD-A, but insufficient data has been presented to evaluate the clinical and cost-effectiveness of PGD-A in the clinical setting. Aneuploidy is a leading cause of implantation failure, miscarriage and congenital abnormalities in humans, and a significant cause of ART failure. Preclinical evidence of PGD-A indicates that the selection and transfer of euploid embryos during ART should improve clinical outcomes. A systematic review of the literature was performed for full text English language articles using MEDLINE, EMBASE, SCOPUS, Cochrane Library databases, NHS Economic Evaluation Database and EconLit. The Downs and Black scoring checklist was used to assess the quality of studies. Clinical effectiveness was measured in terms of pregnancy, live birth and miscarriage rates. Nineteen articles meeting the inclusion criteria, comprising three RCTs in young and good prognosis patients and 16 observation studies were identified. Five of the observational studies included a control group of patients where embryos were selected based on morphological criteria (matched cohort studies). Of the five studies that included a control group and reported implantation rates, four studies (including two RCTs) demonstrated improved implantation rates in the PGD-A group. Of the eight studies that included a control group, six studies (including two RCTs) reported significantly higher pregnancy rates in the PGD-A group, and in the remaining two studies, equivalent pregnancies rates were reported despite fewer embryos being transferred in the PGD-A group. The three RCTs demonstrated benefit in young and good prognosis patients in terms of clinical pregnancy rates and the use of single embryo transfer. However, studies relating to patients of advanced maternal age, recurrent miscarriage and implantation failure were restricted to matched cohort studies, limiting the ability to draw meaningful conclusions. Relevant studies may have been missed and findings from RCTs currently being undertaken could not be included. Given the uncertain role of PGD-A techniques, high-quality experimental studies using intention-to-treat analysis and cumulative live birth rates including the comparative outcomes from remaining cryopreserved embryos are needed to evaluate the overall role of PGD-A in the clinical setting. It is only in this way that the true contribution of PGD-A to ART can be understood.

O-18 Preimplantation genetic diagnosis for aneuploidy and chromosomal translocations: Overall results from a multicenter study

O-18 Preimplantation genetic diagnosis for aneuploidy and chromosomal translocations: Overall results from a multicenter study

LETTER TO THE EDITOR BY MEGAN HALL

Sir, We read with interest the recent review by Santiago Munne entitled, “Preimplantation Genetic Diagnosis for Aneuploidy and Translocations Using Array Comparative Genomic Hybridization” (1). As part of the review of array comparative genome hybridization (aCGH), the author provides additional information on other 24-chromosome preimplantation genetic diagnosis/screening (PGD/PGS) techniques. As a commercial lab that offers single nucleotide polymorphism (SNP) microarray analysis for PGD/PGS, we would like to comment on a few claims that were made within this article regarding SNP microarrays. (Table 1) in the article summarizes the differences between 24-chromosome PGD/PGS techniques. This table contains a number of errors regarding SNP microarray detection capabilities as it groups the different approaches of SNP microarray analysis under a single heading of “SNPs”. SNP technologies that employ a combination of qualitative and quantitative data analysis detect far more abnormalities than those that use just one type of analysis. First, it is not accurate to say that “SNPs” cannot detect tetraploidy. SNP microarrays using qualitative/quantitative analysis can detect some forms of tetraploidy; this method will not detect 2:2 tetraploidy, though is indeed capable of detecting 3:1 tetraploidy. Second, SNP microarray technologies that use a qualitative/quantitative approach can detect meiotic and mitotic duplications without recombination (3); the table incorrectly states that SNP microarray approaches cannot detect these abnormalities. Lastly, it is an exaggeration to state that aCGH approaches are able to detect all unbalanced translocations and SNP microarray approaches can only detect some; both approaches are equally limited in their inability to detect very small deletions and duplications (both have a similar threshold in that they typically detect DNA segments greater than 6Mb). We also question a number of statements the author makes about aCGH and SNP microarray within the body of the paper. The author acknowledges that aCGH cannot detect haploidy or polyploidy but claims that this is a small limitation, as the majority of the haploid or polyploid embryos tested (7.7%) had additional detectable abnormalities; however, these additional abnormalities are not named. It is our experience that other abnormalities are not typically found with 69,XXX. Next, the author credits SNP microarray with the ability to detect uniparental disomy (UPD) but then goes on to use the incidence of UPD of chromosome 15 (UPD-15) to say that UPD in general is a very rare event. Chromosome15 is only one of six imprinted chromosomes (6, 7, 11, 14, 15, and 16), which if UPD is present, could lead to the birth of a baby with a severe genetic syndrome (4). We feel that detection of UPD prior to embryo transfer decisions is highly beneficial to, and desired by, couples undergoing IVF with PGD/PGS. Furthermore, in regards to PGD/PGS for reciprocal and Robertsonian translocations, we would like to clarify that not all SNP microarray approaches can differentiate between normal and balanced (carrier) embryos. Last, the author correctly points out that SNP microarray approaches require parental DNA analysis prior to the embryo sample analysis. However, our lab does not charge a cancellation fee for this parental analysis when IVF cycles are cancelled, thus patients do not pay for unnecessary parental testing. We appreciate that the author mentions SNP microarray analysis that employs a qualitative/quantitative approach will avoid many of the limitations inherent to the purely qualitative or quantitative approaches. However, the review references our article (Johnson DS et al. [2], reference 77 in the original paper) as an aCGH technology, when in fact we utilize a SNP-based approach with bioinformatics analysis. Natera’s PGD/PGS Parental SupportTM method utilizes SNP measurements of parental and embryonic samples, giving us the ability to analyze both qualitative and quantitative data from each chromosome to determine the embryonic chromosomal copy number. In addition, the Parental SupportTM method utilizes a much more sophisticated bioinformatics-based analysis (2) than the combined approach described in the article. New methods should always be validated against more established ones, but given the errors rates reported with FISH PGD/PGS (as stated by the author at the beginning of the paper), we strongly disagree that validation studies using FISH for reanalysis should be considered the gold standard (2, 5). Natera thus supports the creation of an oversight body to administer proficiency testing for laboratories offering 24-chromosome PGD/PGS. Sincerely,

Single-gene testing combined with single nucleotide polymorphism microarray preimplantation genetic diagnosis for aneuploidy: a novel approach in optimizing pregnancy outcome

To describe a method of amplifying DNA from blastocyst trophectoderm cells (two or three cells) and simultaneously performing 23-chromosome single nucleotide polymorphism microarrays and single-gene preimplantation genetic diagnosis. Case report. IVF clinic and preimplantation genetic diagnostic centers. A 36-year-old woman, gravida 2, para 1011, and her husband who both were carriers of GM(1) gangliosidosis. The couple wished to proceed with microarray analysis for aneuploidy detection coupled with DNA sequencing for GM(1) gangliosidosis. An IVF cycle was performed. Ten blastocyst-stage embryos underwent trophectoderm biopsy. Twenty-three-chromosome microarray analysis for aneuploidy and specific DNA sequencing for GM(1) gangliosidosis mutations were performed. Viable pregnancy. After testing, elective single embryo transfer was performed followed by an intrauterine pregnancy with documented fetal cardiac activity by ultrasound. Twenty-three-chromosome microarray analysis for aneuploidy detection and single-gene evaluation via specific DNA sequencing and linkage analysis are used for preimplantation diagnosis for single-gene disorders and aneuploidy. Because of the minimal amount of genetic material obtained from the day 3 to 5 embryos (up to 6 pg), these modalities have been used in isolation of each other. The use of preimplantation genetic diagnosis for aneuploidy coupled with testing for single-gene disorders via trophectoderm biopsy is a novel approach to maximize pregnancy outcomes. Although further investigation is warranted, preimplantation genetic diagnosis for aneuploidy and single-gene testing seem destined to be used increasingly to optimize ultimate pregnancy success.

Increased efficiency of preimplantation genetic diagnosis for aneuploidy by testing 12 chromosomes

One of the most important factors in increasing the screening potential of preimplantation genetic diagnosis (PGD) for aneuploidy is to increase the number of chromosomes analysed. Inclusion of chromosomes 8, 14 and 20 to the standard set of chromosomes X, Y, 13, 15, 16, 17, 18, 21 and 22 allows the analysis of 12 chromosomes in three rounds of fluorescent in-situ hybridization (FISH) without decreasing the efficiency of the technique. Pregnancy rate was significantly increased when only embryos that had been diagnosed as normal for the 12 chromosomes analysed were transferred compared with transfer of embryos with any abnormality for chromosomes 8, 14 or 20 (P < 0.05). This study proves that the high efficiency and practical feasibility of FISH analysis of 12 chromosomes in PGD for aneuploidy is a superior approach than the standard nine-chromosome analysis in order to screen for abnormalities.

Prospectively randomized controlled trial of PGS in IVF/ICSI patients with poor implantation

This randomized, controlled trial verifies whether patients with recurrent failed implantation benefit from preimplantation genetic diagnosis for aneuploidy, as compared with conventional assisted reproduction treatment procedures. Two hundred patients with recurrent failed implantation were randomized into two groups. A total of 139 patients underwent ovarian stimulation, and preimplantation genetic screening was performed in 72 patients. Analysis of chromosomes X, Y, 13, 16, 18, 21 and 22 was carried out using fluorescence in-situ hybridization in blastomeres of day-3 cleavage-stage embryos in the study group. The primary endpoint was implantation rate. Secondary endpoints were embryonic morphology and chromosomal status, number of transferred embryos and clinical pregnancy rate. With regard to the implantation rate, there was no significant difference between the study group (21.4%) and the control group (25.3%). The number of embryos transferred was significantly lower in the study group, namely 1.4 (SD 1.0) versus 2.1 (SD 1.0) in the control group ( P < 0.05). The clinical pregnancy rate was not significantly different between the groups (25.0% in the study group versus 40.3% in the control group). It can be concluded that preimplantation genetic screening does not increase the implantation rates after IVF–intracytoplasmic sperm injection in women with repeated implantation failure.

Monosomy rescue in preimplantation genetic diagnosis of aneuploidy

Monosomy rescue in preimplantation genetic diagnosis of aneuploidy

Ten-year experience with preimplantation genetic diagnosis (PGD) at the New York University School of Medicine Fertility Center

We describe our experience of over 300 cycles of preimplantation genetic diagnosis (PGD) and report clinical pregnancy rates (35%-67%) that support using this technology to screen for genetic disorders and chromosomal abnormalities. In clinical practice for over ten years, PGD offers couples the earliest form of genetic screening and may help improve ongoing pregnancy rates in poor-prognosis patients.