Preimplantation genetic testing for aneuploidy by microarray analysis of polar bodies in advanced maternal age: a randomized clinical trial.

STUDY QUESTION: Does preimplantation genetic testing for aneuploidy (PGT-A) by comprehensive chromosome screening (CCS) of the first and second polar body to select embryos for transfer increase the likelihood of a live birth within 1 year in advanced maternal age women aged 36-40 years planning an ICSI cycle, compared to ICSI without chromosome analysis? SUMMARY ANSWER: PGT-A by CCS in the first and second polar body to select euploid embryos for transfer does not substantially increase the live birth rate in women aged 36-40 years. WHAT IS KNOWN ALREADY: PGT-A has been used widely to select embryos for transfer in ICSI treatment, with the aim of improving treatment effectiveness. Whether PGT-A improves ICSI outcomes and is beneficial to the patients has remained controversial. STUDY DESIGN, SIZE, DURATION: This is a multinational, multicentre, pragmatic, randomized clinical trial with intention-to-treat analysis. Of 396 women enroled between June 2012 and December 2016, 205 were allocated to CCS of the first and second polar body (study group) as part of their ICSI treatment cycle and 191 were allocated to ICSI treatment without chromosome screening (control group). Block randomization was performed stratified for centre and age group. Participants and clinicians were blinded at the time of enrolment until the day after intervention. PARTICIPANTS/MATERIALS, SETTING, METHODS: Infertile couples in which the female partner was 36-40 years old and who were scheduled to undergo ICSI treatment were eligible. In those assigned to PGT-A, array comparative genomic hybridization (aCGH) analysis of the first and second polar bodies of the fertilized oocytes was performed using the 24sure array of Illumina. If in the first treatment cycle all oocytes were aneuploid, a second treatment with PB array CGH was offered. Participants in the control arm were planned for ICSI without PGT-A. Main exclusion criteria were three or more previous unsuccessful IVF or ICSI cycles, three or more clinical miscarriages, poor response or low ovarian reserve. The primary outcome was the cumulative live birth rate after fresh or frozen embryo transfer recorded over 1 year after the start of the intervention. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 205 participants in the chromosome screening group, 50 (24%) had a live birth with intervention within 1 year, compared to 45 of the 191 in the group without intervention (24%), a difference of 0.83% (95% CI: -7.60 to 9.18%). There were significantly fewer participants in the chromosome screening group with a transfer (relative risk (RR) = 0.81; 95% CI: 0.74-0.89) and fewer with a miscarriage (RR = 0.48; 95% CI: 0.26-0.90). LIMITATIONS, REASONS FOR CAUTION: The targeted sample size was not reached because of suboptimal recruitment; however, the included sample allowed a 90% power to detect the targeted increase. Cumulative outcome data were limited to 1 year. Only 11 patients out of 32 with exclusively aneuploid results underwent a second treatment cycle in the chromosome screening group. WIDER IMPLICATIONS OF THE FINDINGS: The observation that the similarity in birth rates was achieved with fewer transfers, less cryopreservation and fewer miscarriages points to a clinical benefit of PGT-A, and this form of embryo selection may, therefore, be considered to minimize the number of interventions while producing comparable outcomes. Whether these benefits outweigh drawbacks such as the cost for the patient, the higher workload for the IVF lab and the potential effect on the children born after prolonged culture and/or cryopreservation remains to be shown. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by the European Society of Human Reproduction and Embryology. Illumina provided microarrays and other consumables necessary for aCGH testing of polar bodies. M.B.'s institution (UZBrussel) has received educational grants from IBSA, Ferring, Organon, Schering-Plough, Merck and Merck Belgium. M.B. has received consultancy and speakers' fees from Organon, Serono Symposia and Merck. G.G. has received personal fees and non-financial support from MSD, Ferring, Merck-Serono, Finox, TEVA, IBSA, Glycotope, Abbott and Gedeon-Richter as well as personal fees from VitroLife, NMC Healthcare, ReprodWissen, BioSilu and ZIVA. W.V., C.S., P.M.B., V.G., G.A., M.D., T.E.G., L.G., G.Ka., G.Ko., J.L., M.C.M., M.P., A.S., M.T., K.V., J.G. and K.S. declare no conflict of interest. TRIAL REGISTRATION NUMBER: NCT01532284. TRIAL REGISTRATION DATE: 7 February 2012. DATE OF FIRST PATIENT'S ENROLMENT: 25 June 2012.

Is genetic fatherhood within reach for all azoospermic Klinefelter men?

BACKGROUND: Multidisciplinary management of Klinefelter cases is now considered good clinical practice in order to ensure optimal quality of life. Reproductive performance of Klinefelter men is an important issue however literature in this domain is limited and prone to bias. STUDY DESIGN: This was a retrospective longitudinal cohort study performed at a tertiary referral University Centre for Reproductive Medicine and Genetics. One hundred thirty-eight non-mosaic azoospermic Klinefelter patients undergoing their first testicular biopsy (TESE) between 1994 and 2013, followed by intracytoplasmic sperm injection (ICSI) with fresh or frozen-thawed testicular sperm in the female partner, were followed-up longitudinally. The main outcome measure was cumulative live birth rate per Klinefelter patient embarking on TESE-ICSI. FINDINGS: In forty-eight men (48/138) sperm were successfully retrieved at the first TESE (34.8%). The mean age of the patients was 32.4 years. Younger age at first TESE was associated with a higher sperm retrieval rate (p<0.001). Overall 39 couples underwent 62 ICSI cycles and 13 frozen embryo transfer cycles resulting in in 20 pregnancies and 14 live birth deliveries (16 children). The mean age of the female partner was 28.1 years. The crude cumulative delivery rate after four ICSI cycles was 35.9%. Per intention-to-treat however, only 10.1% (14/138) of the Klinefelter men starting treatment succeeded in having their biologically own child(ren). CONCLUSION: Non-mosaic Klinefelter patients with azoospermia seeking treatment by TESE-ICSI should be counseled that by intention-to-treat the chance of retrieving sperm is fair, however only a minority will eventually father genetically own children.

Gonadotropin Releasing Hormone Agonists or Antagonists for Preimplantation Genetic Diagnosis (PGD)? A Prospective Randomised Trial.

BACKGROUND: The use of GnRH analogue medication is essential in reproductive medicine to avoid premature ovulation by pituitary suppression for the duration of ovarian stimulation by gonadotrophins. The type of pituitary suppression by either GnRH agonist analogues versus GnRH antagonist analogues may result in different embryological hence clinical results. Preimplantation genetic diagnosis is a subtype of IVF in which embryos are created for genetic diagnosis of hereditary disorders in order to avoid genetically affected children. Embryological quality hence ovarian stimulation in preimplantation genetic diagnosis is crucial as genetic selection will reduce the number of available embryos to a fraction of the total. OBJECTIVE: The aim of this study was to assess the efficiency of GnRH antagonist versus GnRH agonist treatment for pituitary suppression in ovarian stimulation for PGD, by proxy of number and quality of embryos at cleavage stage available for biopsy. METHOD: We conducted a prospective randomised controlled trial comparing pituitary suppression by GnRH antagonist versus GnRH agonist in ovarian stimulation for PGD. The primary outcome measure was the number of embryos of sufficient quality for biopsy at cleavage stage. Secondary outcome parameters were the number of blastocysts available of top quality, and clinical pregnancy rate. RESULTS: There was no difference in number of oocytes retrieved, embryos at cleavage stage available for biopsy or embryo quality. The clinical pregnancy rate was higher in the GnRH agonist group; however the sample size was insufficient to allow conclusions. CONCLUSION: The use of GnRH agonist versus antagonist treatment does not result in differences in a number of oocytes, embryos or embryo quality in ovarian stimulation for preimplantation genetic diagnosis.

Low-grade chromosomal mosaicism in human somatic and embryonic stem cell populations.

Current knowledge on chromosomal mosaicism in human cell cultures is mostly based on cytogenetic banding methods. The recent development of high-resolution full-genome analysis methods applicable to single cells is providing new insights into genetic and cellular diversity. Here we study the genetic content of 92 individual human cells, including fibroblasts, amniocytes and embryonic stem cells (hESCs), using single-cell array-based comparative genomic hybridization (aCGH). We find that human somatic and embryonic stem cell cultures show significant fractions of cells carrying unique megabase-scale chromosomal abnormalities, forming genetic mosaics that could not have been detected by conventional cytogenetic methods. These findings are confirmed by studying seven clonal hESC sub-lines by aCGH. Furthermore, fluorescent in situ hybridisation reveals an increased instability of the subtelomeric regions in hESC as compared to somatic cells. This genetic heterogeneity may have an impact on experimental results and, in the case of hESC, on their potential clinical use.

Preimplantation genetic diagnosis in female and male carriers of reciprocal translocations: clinical outcome until delivery of 312 cycles.

Carriers of reciprocal translocations (rcp) are known to be at risk for reproductive difficulties. Preimplantation genetic diagnosis (PGD) is one of the options these carriers have to try in order to fulfil their desire to have a child. In the present study, we retrospectively looked at the results of 11 years (1997-2007) of PGD for rcp in our center to improve the reproductive counseling of these carriers. During this period 312 cycles were performed for 69 male and 73 female carriers. The mean female age was 32.8 years, the mean male age 35.8 years. Most carriers were diagnosed with a translocation because of fertility problems or recurrent miscarriages, and most of them opted for PGD to avoid these problems. In 150 of the 312 cycles, embryo transfer (ET) was feasible and 40 women had a successful singleton or twin pregnancy. This gives a live birth delivery rate of 12.8% per started cycle and of 26.7% per cycle with ET. Owing to the large number of abnormal embryos, PGD cycles for rcp often lead to cancellation of ET, explaining the low success rate when expressed per cycle with oocyte pick-up. Once ET was feasible, the live birth delivery rate was similar to that of PGD in general at our center. PGD is therefore an established option for specific reciprocal translocation carriers.

Pregnancy outcome in carriers of Robertsonian translocations.

Robertsonian translocation carriers are at increased risk for infertility, spontaneous abortions, or chromosomally unbalanced offspring. Reproductive counseling of these carriers is challenging. We performed a retrospective analysis of all prenatal diagnoses from Robertsonian translocation carriers during the time period January 1, 1992 through December 31, 2007. Data on the carriers and the results of their prenatal analyses were retrieved as well as data on their previous pregnancies. We identified 28 female and 20 male carriers of Robertsonian translocations and results on 79 prenatal samples were obtained. Among female carriers, 10.3% of chorionic villus sampling and 5.9% of amniocentesis results were unbalanced, whereas for male carriers, this was 3.6% and 0%, respectively. When considering all pregnancies involving carriers, 52.7% of those to female carriers and 61.8% of those to male carriers led to the birth of a healthy child. Male carriers in whom the translocation was ascertained because of infertility or recurrent miscarriages appear to be at higher risk, whereas carriers in whom ascertainment was because of a family history are at lower risk. We conclude that pregnancies of Robertsonian translocation carriers are at increased risk for chromosomal imbalance, and prenatal chromosomal testing should be discussed. More than half of the pregnancies led to the birth of a healthy child, but prediction of which couples will be successful in obtaining a pregnancy with or without assisted reproductive technologies and/or embryo selection remains difficult. The reason for ascertainment of the translocation should be taken into account when counseling these couples. The possibility of preimplantation genetic diagnosis should also be discussed with the couples.

Polar body array CGH for prediction of the status of the corresponding oocyte. Part I: clinical results.

BACKGROUND: Several randomized controlled trials have not shown a benefit from preimplantation genetic screening (PGS) biopsy of cleavage-stage embryos and assessment of up to 10 chromosomes for aneuploidy. Therefore, a proof-of-principle study was planned to determine the reliability of alternative form of PGS, i.e. PGS by polar body (PB) biopsy, with whole genome amplification and microarray-based comparative genomic hybridization (array CGH) analysis. METHODS: In two centres, all mature metaphase II oocytes from patients who consented to the study were fertilized by ICSI. The first and second PBs (PB1and PB2) were biopsied and analysed separately for chromosome copy number by array CGH. If either or both of the PBs were found to be aneuploid, the corresponding zygote was then also processed by array CGH for concordance analysis. RESULTS: Both PBs were biopsied from a total of 226 zygotes from 42 cycles (average 5.5 per cycle; range 1-15) in 41 couples with an average maternal age of 40.0 years. Of these, the ploidy status of the zygote could be predicted in 195 (86%): 55 were euploid (28%) and 140 were aneuploid (72%). With only one exception, there was at least one predicted aneuploid zygote in each cycle and in 19 out of 42 cycles (45%), all zygotes were predicted to be aneuploid. Fresh embryos were transferred in the remaining 23 cycles (55%), and one frozen transfer was done. Eight patients had a clinical pregnancy of which seven were evolutive (ongoing pregnancy rates: 17% per cycle and 30% per transfer). The ploidy status of 156 zygotes was successfully analysed by array CGH: 38 (24%) were euploid and 118 (76%) were aneuploid. In 138 cases complete information was available on both PBs and the corresponding zygotes. In 130 (94%), the ploidy status of the zygote was concordant with the ploidy status of the PBs and in 8 (6%), the results were discordant. CONCLUSIONS: This proof-of-principle study indicates that the ploidy of the zygote can be predicted with acceptable accuracy by array CGH analysis of both PBs.

No relationship between the type of pituitary suppression for IVF and chromosomal abnormality rates of blastomeres: an observational study.

OBJECTIVE: To investigate whether the incidence of chromosomally abnormal blastomeres is related to the type of pituitary suppression used in ovarian stimulation. DESIGN: Retrospective study. SETTING: Tertiary referral center. PATIENT(S): The study involved 694 consecutive cycles; 320 belonged to agonist group and 374 to antagonist group, of patients' ≤ 37 years of age who underwent preimplantation genetic screening between October 1, 1992 until December 31, 2006. All of them (and their partners) had normal karyotyping results. Only the data of patients who had at least one embryo biopsy were analyzed. INTERVENTION(S): Preimplantation genetic screening (PGS). MAIN OUTCOME MEASURE(S): The primary outcome measure was detection of abnormal blastomeres on the total number of embryos analyzed. RESULT(S): The total abnormal ratio was statistically similar between the embryos of the two study groups (49.9 ± 28.1 vs. 50.2 ± 26.6). Likewise, a multivariate (linear regression) analysis indicated that the total abnormality ratio was not influenced by the type of stimulation when simultaneously adjusting for age, rank of trials, indication for preimplantation genetic screening, total gonadotropin amount, number of cumulus-oocyte complexes, and number of two pronuclear oocytes embryos. No difference was observed in ongoing pregnancy rates between agonists and antagonists (26.6% vs. 23.3%, respectively). CONCLUSION(S): Based on our findings there is no difference in the proportion of abnormal blastomeres either when using gonadotropin-releasing hormone (GnRH) agonist, or antagonist protocol.

Prognostic factors for delivery in patients undergoing repeated preimplantation genetic aneuploidy screening.

We performed a retrospective analysis of patients who had a first failed preimplantation genetic aneuploidy screening (PGS) cycle. At least one euploid embryo was found in 64% of the patients who had no euploid embryos available on their first PGS cycle. A previous failed treatment because of lack of euploid embryos does not contraindicate a further assisted reproductive cycle.

What next for preimplantation genetic screening? High mitotic chromosome instability rate provides the biological basis for the low success rate.

Preimplantation genetic screening is being scrutinized, as recent randomized clinical trials failed to observe the expected significant increase in live birth rates following fluorescence in situ hybridization (FISH)-based screening. Although these randomized clinical trials are criticized on their design, skills or premature stop, it is generally believed that well-designed and well-executed randomized clinical trials would resolve the debate about the potential benefit of preimplantation genetic screening. Since FISH can analyze only a limited number of chromosomal loci, some of the embryos transferred might be diagnosed as 'normal' but in fact be aneuploid for one or more chromosomes not tested. Hence, genome-wide array comparative genome hybridization screening enabling aneuploidy detection of all chromosomes was thought to be a first step toward a better design. We recently showed array screening indeed enables accurate determination of the copy number state of all chromosomes in a single cell. Surprisingly, however, this genome-wide array screening revealed a much higher frequency and complexity of chromosomal aberrations in early embryos than anticipated, with imbalances in a staggering 90% of all embryos. The mitotic error rate in cleavage stage embryos was proven to be higher than the meiotic aneuploidy rate and as a consequence, the genome of a single blastomere is not representative for the genome of the other cells of the embryo. Hence, potentially viable embryos will be discarded upon screening a single blastomere. This observation provides a biological basis for the failure of the randomized clinical trials to increase baby-take-home rates using FISH on cleavage stage embryos.

A proposal for reproductive counselling in carriers of Robertsonian translocations: 10 years of experience with preimplantation genetic diagnosis.

BACKGROUND: Carriers of Robertsonian translocations are at increased risk for infertility, repeated miscarriage and aneuploid offspring. In the present study, 10 years of experience with preimplantation genetic diagnosis (PGD) for Robertsonian translocations is reviewed and these data are used to improve the reproductive counselling in the carriers. METHODS: A retrospective analysis was performed of all requests and cycles for PGD for Robertsonian translocations at our centre between January 1997 and December 2006. Data on the characteristics of the couples and on the PGD cycles were retrieved from the medical records. These data were recorded for the whole group and according to the sex of the carrier. RESULTS: A total of 111 couples made a request for PGD in our centre, of which 76 had at least one PGD cycle. In the PGD cycles embryo transfer could take place in 66.1% of the cycles with oocyte pick-up and positive hCG was found in 42.7% of the cycles with embryo transfer. The live born delivery rate was 20.2% per cycle with oocyte retrieval and 30.5% per cycle with embryo transfer. CONCLUSIONS: With a live birth delivery rate of 32.9% per couple, PGD is considered a good option for these couples, especially when there is a coexisting fertility problem. PGD reduces the risk of miscarriage and allows couples to have a healthy child within a relatively short time span compared with spontaneous pregnancies. However, for young, fertile couples, the chances of having a healthy child after a number of spontaneous pregnancies, should not be ignored.

Two-year auxological and medical outcome of singletons born after embryo biopsy applied in preimplantation genetic diagnosis or preimplantation genetic screening.

BACKGROUND: Embryo biopsy is an essential but invasive procedure to perform preimplantation genetic diagnosis (PGD) or preimplantation genetic screening (PGS). The major objective of this study was to determine whether embryo biopsy might cause post-natal growth restriction. METHODS: We compared growth data and physical findings at birth and 2 years for singletons born either after PGD/PGS (n = 70), ICSI (n = 70) or natural conception (NC) (n = 70). Children were matched for gender, maternal educational level, mother tongue and birth order. RESULTS: No significant differences were found between the three groups regarding weight, height and head circumference standard deviation scores (SDS) at birth and at age 2 years, although the PGD/PGS children tended to have a lower birthweight compared with the NC children. At 2 years, the mean BMI SDS in PGD/PGS children was significantly lower compared with NC children (P = 0.005). PGD/PGS children were more frequently born after Caesarian section than ICSI children, but had no more congenital malformations, hospital admissions and surgical interventions compared with ICSI and NC children. CONCLUSIONS: Singleton children at age 2 years born after embryo biopsy applied in PGD/PGS present a similar post-natal linear growth compared with ICSI and NC children. PGD/PGS singletons appear not to be at higher risk for congenital malformations and surgical interventions during the first 2 years of life. To date, there have been no observable detrimental effects of the PGD/PGS procedure on children.

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.

Recurrent chromosomal abnormalities in human embryonic stem cells.

Cultured human embryonic stem (hES) cells have a known predisposition to aneuploidy of chromosomes 12, 17 and X. We studied 17 hES cell lines by array-based comparative genomic hybridization (aCGH) and found that the cells accumulate other recurrent chromosomal abnormalities, including amplification at 20q11.21 and a derivative chromosome 18. These genomic changes have a variable impact at the transcriptional level.

First successful bone marrow transplantation for X-linked chronic granulomatous disease by using preimplantation female gender typing and HLA matching.

Allogeneic hematopoietic stem cell transplantation from an human leukocyte antigen (HLA)-identical donor is currently the only proven curative treatment for chronic granulomatous disease. Hematopoietic stem cell transplantation with alternative donors is associated with higher morbidity and mortality. Therefore, we performed in vitro fertilization and preimplantation HLA matching combined with female sexing for hematopoietic stem cell transplantation in chronic granulomatous disease. Ethical and psychological issues were considered carefully. We used in vitro fertilization with X-enriched spermatozoa followed by preimplantation genetic diagnosis to identify female HLA-genoidentical embryos in a family in need of a suitable donor for their boy affected with severe X-linked chronic granulomatous disease. Two preimplantation genetic diagnosis cycles were performed in the family. In the second cycle, 2 HLA-genoidentical female embryos were transferred and a singleton pregnancy was obtained, resulting in the birth of an unaffected girl at term. Because of insufficient cell numbers in the cord-blood source, conventional hematopoietic stem cell transplantation had to be performed at 12 months of age of the donor and 5 years of age of the recipient and resulted in complete stable donor chimerism and immunologic reconstitution up to 25 months post-hematopoietic stem cell transplantation. Hematopoietic stem cell transplantation after in vitro fertilization and combined female sexing and HLA matching offers a new and relatively rapid therapeutic option for patients with X-linked primary immunodeficiency such as chronic granulomatous disease who need hematopoietic stem cell transplantation but lack an HLA-genoidentical donor.

Diagnostic efficiency, embryonic development and clinical outcome after the biopsy of one or two blastomeres for preimplantation genetic diagnosis.

BACKGROUND: Preimplantation genetic diagnosis or screening (PGD, PGS) involves embryo biopsy on Day 3. Opting for one- or two-cell biopsy is a balance between the lowest risk for misdiagnosis on the one hand and the highest chance for a pregnancy on the other hand. METHODS: A prospective controlled trial was designed and 592 ICSI cycles were randomly assigned to the one-cell (group I) or the two-cell group (group II). Primary outcomes were diagnostic efficiency and embryonic development to delivery with live birth (analysed by cycle). The false-positive rate for the PCR cycles is presented as a secondary outcome (analysed by embryo). RESULTS: A strong significant correlation was observed between embryonic developmental stage on Day 3 and post-biopsy in vitro development on Day 5 (P < 0.0001). The influence of the intervention on Day 3 was less significant (P = 0.007): the biopsy of one cell is less invasive than the biopsy of two cells. PCR diagnostic efficiency was 88.6% in group I and 96.4% in group II (P = 0.008). For the fluorescence in situ hybridization (FISH) PGD cycles no significant difference in efficiency was obtained (98.2 and 97.5% in group I and II, respectively). Similar delivery rates with live birth per started cycle were obtained [58/287 or 20.2% in group I versus 52/303 or 17.2% in group II, P = 0.358; the absolute risk reduction = 3.05%; 95% confidence interval (CI): -3.24, 9.34]. Post-PGD PCR reanalysis showed six false positives in 97 embryos (6.2%) in group II and none in group I (91 embryos reanalysed). No false negatives were found. CONCLUSIONS: While removal of two blastomeres decreases the likelihood of blastocyst formation, compared with removal of one blastomere, Day 3 in vitro developmental stage is a stronger predictor for Day 5 developmental potential than the removal of one or two cells. The biopsy of only one cell significantly lowers the efficiency of a PCR-based diagnosis, whereas the efficiency of the FISH PGD procedure remains similar whether one or two cells are removed. Delivery rates with live birth per started cycle were not significantly different.

The analysis of one or two blastomeres for PGD using fluorescence in-situ hybridization.

BACKGROUND: The analysis of one or two blastomeres for PGD using fluorescence in-situ hybridization (FISH) is debated. The proportion of analysable embryos, false negatives, false positives, sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and efficiency were evaluated when one or two blastomeres were analysed. METHODS: Embryos of patients having PGD for aneuploidy screening were assigned non-randomly to two groups: group I (n = 413), more slow cleaving embryos with one nucleus for analysis, and group II (n = 1366), regularly cleaving embryos with two nuclei for analysis. A two-round FISH procedure was performed investigating seven chromosomes; 486 embryos were reanalysed. RESULTS: The proportion of analysable embryos was significantly higher in group II (98.2 versus 95.9%) (P = 0.04). Despite the apparently increased false-positive rate (group I: 25.6% and group II: 13.6%) and the decreased PPV (group I: 91.9% and group II: 96.7%), specificity (group I: 74.4% and group II: 86.4%) and efficiency (group I: 93.5% and group II: 97.3%) in group I, no significance was reached (P = 0.11, P = 0.053, P = 0.11 and P = 0.06, respectively). CONCLUSIONS: Although the analysis of one blastomere generates statistically significantly fewer embryos with a diagnosis than does the analysis of two blastomeres, the 2% difference may not be clinically relevant. The diagnostic accuracy is not significantly different between the two groups, hence not favouring the analysis of one or two blastomeres.

The importance of aneuploidy screening in reciprocal translocation carriers.

The purpose of this study is to investigate the aneuploidy rate and the mosaicism of chromosomes not involved in reciprocal translocations. Aneuploidy screening (AS) (13, 16, 18, 21 and 22) was performed as a re-analysis on fixed blastomeres from 126 embryos already analysed in preimplantation genetic diagnosis (PGD) cycles of eight female and five male reciprocal translocation carriers who had not achieved a pregnancy. A successful diagnosis for AS was achieved in 91.3% of embryos; 30.9% were euploid and 60.3% were aneuploid for the five chromosomes analysed. Of the embryos, 8.7% were euploid for AS and normal-balanced for the translocation and 22.2% were euploid for AS but unbalanced for the translocation; 8% of the embryos were aneuploid for AS but normal-balanced for the translocation and 52.4% were aneuploid for AS and also unbalanced for the translocation. At least 58.7% of the embryos were mosaic regarding mosaicism for the chromosomes involved and not involved in the translocations. Six of the 16 embryos transferred in the PGD cycles were aneuploid for the AS study; four of them were also mosaics. AS should be performed in reciprocal translocation carriers after segregation analysis in PGD.

Single-cell chromosomal imbalances detection by array CGH.

Genomic imbalances are a major cause of constitutional and acquired disorders. Therefore, aneuploidy screening has become the cornerstone of preimplantation, prenatal and postnatal genetic diagnosis, as well as a routine aspect of the diagnostic workup of many acquired disorders. Recently, array comparative genomic hybridization (array CGH) has been introduced as a rapid and high-resolution method for the detection of both benign and disease-causing genomic copy-number variations. Until now, array CGH has been performed using a significant quantity of DNA derived from a pool of cells. Here, we present an array CGH method that accurately detects chromosomal imbalances from a single lymphoblast, fibroblast and blastomere within a single day. Trisomy 13, 18, 21 and monosomy X, as well as normal ploidy levels of all other chromosomes, were accurately determined from single fibroblasts. Moreover, we showed that a segmental deletion as small as 34 Mb could be detected. Finally, we demonstrated the possibility to detect aneuploidies in single blastomeres derived from preimplantation embryos. This technique offers new possibilities for genetic analysis of single cells in general and opens the route towards aneuploidy screening and detection of unbalanced translocations in preimplantation embryos in particular.

Preimplantation genetic diagnosis for aneuploidy screening in women older than 37 years.

OBJECTIVE: To provide background information about the average aneuploidy and implantation rates of older patients after IVF with preimplantation genetic diagnosis for aneuploidy screening (PGD-AS) when the patients are subdivided into age categories; and to compare pregnancy outcome data after PGD-AS in this group of patients with a similar control group. DESIGN: Retrospective clinical study. SETTING: Patients in an academic reproductive medicine unit. PATIENT(S): All patients 37 years or older who had PGD-AS between October 1999 and December 2003 and all pregnant patients 37 years or older who had IVF/intracytoplasmic sperm injection without PGD-AS during the same period of time. INTERVENTION(S): IVF with PGD-AS. MAIN OUTCOME MEASURE(S): Aneuploidy rate, miscarriage rate, live birth rate, implantation rate, multiple pregnancy rate, and prenatal testing. RESULT(S): Three hundred ninety-four PGD-AS cycles of patients between 37 and 46 years of age were analyzed. The aneuploidy rate gradually increased with age. The implantation rate remained similar over all age groups. There was a trend to a lower miscarriage and multiple pregnancy rate in the PGD-AS group and a higher delivery/live birth rate. There were five elective terminations of pregnancy after prenatal testing and three late miscarriages due to prenatal testing in the control group. CONCLUSION(S): Preimplantation genetic diagnosis for aneuploidy screening can give valuable information to older patients concerning the reason why their IVF cycles are unsuccessful and whether it is worthwhile to continue IVF treatment, and it can help patients to avoid the emotional trauma that can occur after prenatal testing during the second trimester of pregnancy.