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S Munné

Publications and source records attributed to S Munné.

At least 19 recordsLinked to original sources
PubMed2006

Wide range of chromosome abnormalities in the embryos of young egg donors.

Embryo chromosome studies show high rates of abnormalities, above 50%, but most embryos studied were from patients aged 35 and older. The objectives of this study were firstly, to evaluate the rate of chromosome abnormalities in embryos from young egg donors, and secondly, to compare the range of chromosome abnormality rates between donors and non-egg donor cycles, both undergoing preimplantation genetic diagnosis (PGD) for infertility using fluorescence in-situ hybridization analysis with probes for chromosomes X, Y, 13, 15, 16, 18, 21, and 22. On average, only 43% of the embryos were chromosomally normal, while the comparison group had euploidy rates between 34 (age group 18-34) (P < 0.001) and 21% (age group 40-45) (P < 0.001). There was considerable variation between donor cycles, with almost one-third having less than 30% normal embryos. Also, within donors and recipients repeating several IVF cycles with PGD, only 29-56% of the second PGD cycles had similar rates of normal embryos to the first cycle, while in the comparison group it was 64%. The results can explain why some egg donors are successful whereas others are not, and may also show that a policy of PGD for first time egg donors is appropriate and indicated.

Adolescent↗
PubMed2005

Karyotyping of human oocytes by cenM-FISH, a new 24-colour centromere-specific technique.

BACKGROUND: Metaphase II (MII) chromosome complements are difficult to karyotype. The objective of this study was to investigate the efficiency and limitations of centromere-specific multiplex fluorescence in situ hybridization (cenM-FISH), a new 24 colour FISH technique using centromere-specific probes, to analyse the whole chromosome complement within human oocytes. METHODS: Oocytes were donated by 34 patients undergoing ovarian stimulation and IVF. The MII oocytes were analysed by means of cenM-FISH, while the confirmation of results was performed by FISH and/or by analysing the corresponding first polar bodies using comparative genomic hybridization (CGH). RESULTS: A total of 30 cells, corresponding to 16 oocytes and 14 first polar bodies, were successfully karyotyped by either cenM-FISH or CGH. The incidence of aneuploidy was 25%, and eight out of nine aneuploidy events were confirmed by CGH and FISH. CONCLUSIONS: We demonstrate here for the first time that the identification of any numerical abnormality in oocytes is feasible using cenM-FISH. Despite the fact that the fixation efficiency remains low, the present results confirm the advantage of analysing the whole set of chromosomes to make an accurate estimation of the aneuploidy rate in human oocytes.

Adult↗
PubMed2005

Aneuploidy 12 in a Robertsonian (13;14) carrier: Case report.

In translocation carriers, the presence of aneuploidy for the chromosomes unrelated to the rearrangement may lead to an additional risk of abnormal pregnancy or implantation failure. Consequently, it may be important to analyse not only the chromosomes involved in the rearrangement but also the rest of chromosomes. We combined spectral karyotyping (SKY) and comparative genomic hybridization (CGH) to karyotype one unfertilized oocyte and its first polar body (1PB) from a Robertsonian translocation carrier t(13;14) aged 29 years who was undergoing IVF and preimplantation genetic diagnosis (PGD) for translocations and aneuploidy screening. Two out of four embryos were aneuploid, as a result of an adjacent segregation. The unfertilized oocyte had a normal/ balanced constitution of the chromosomes involved in the reorganization. However, this 1PB-metaphase II doublet was aneuploid for chromosome 12, the oocyte being hyperhaploid (24, X, +12) and its 1PB hypohaploid (22, X, -12). The application of CGH for the study of Robertsonian translocations of maternal origin will be useful to study imbalances of the chromosomes involved in the rearrangement, as well as alterations in the copy number of any other chromosome. The combination of PGD for translocations with aneuploidy screening could help to reduce the replacement of chromosomally abnormal embryos.

Abortion, Habitual↗
PubMed2005

Analysis of chromosome segregation during preimplantation genetic diagnosis in both male and female translocation heterozygotes.

Individuals carrying translocations suffer from reduced fertility or spontaneous abortions and seek help in form of assisted reproductive technology (ART) and preimplantation genetic diagnosis (PGD). While most translocations are relatively easy to detect in metaphase cells, the majority of embryonic cells biopsied in the course of in vitro fertilization (IVF) procedures are in interphase. These nuclei are thus unsuitable for analysis by chromosome banding or painting using fluorescence in situ hybridization (FISH). Thus several methods have been devised to detect translocation imbalance through FISH in single cells for purpose of PGD, among them polar body chromosome painting, interphase FISH with combination of subtelomeric and centromeric probes, breakpoint spanning probes, and cell conversion. Results with PGD indicate a significant decrease in spontaneous abortions, from 81% before PGD to 13% after PGD. They also indicate very high rates of chromosome abnormalities in embryos from translocation carriers, 72% for Robertsonian translocations and 82% for reciprocal translocations. Sperm analysis was found to be a good predictor of IVF and PGD outcome, with samples with more than 60% abnormal forms indicating poor prognosis. Similarly, the predictability from first PGD cycle results for future cycles was 90%. In summary, PGD can help translocation carriers to achieve viable pregnancies, but the success of the process is conversely related to the baseline of unbalanced gametes.

Blastula↗
PubMed2004

Aneuploidy study of human oocytes first polar body comparative genomic hybridization and metaphase II fluorescence in situ hybridization analysis.

BACKGROUND: The object of this study was to determine the mechanisms that produce aneuploidy in oocytes and establish which chromosomes are more prone to aneuploidy. METHODS: A total of 54 oocytes from 36 women were analysed. The whole chromosome complement of the first polar body (1PB) was analysed by comparative genomic hybridization (CGH), while the corresponding metaphase II (MII) oocyte was analysed by fluorescence in situ hybridization (FISH) to confirm the results. RESULTS: Matched CGH-FISH results were obtained in 42 1PB-MII doublets, of which 37 (88.1%) showed reciprocal results. The aneuploidy rate was 57.1%. Two-thirds of the aneuploidy events were chromatid abnormalities. Interestingly, the chromosomes more frequently involved in aneuploidy were chromosomes 1, 4 and 22 followed by chromosome 16. In general, small chromosomes (those equal to or smaller in size than chromosome 13) were more prone to aneuploidy (chi2-test, P=0.07); 25% of the aneuploid doublets would have been misdiagnosed as normal using FISH with probes for nine-chromosomes. CONCLUSIONS: The combination of two different techniques, CGH and FISH, for the study of 1PB and MII allowed the identification and confirmation of any numerical chromosome abnormality, as well as helping to determine the mechanisms involved in the genesis of maternal aneuploidy.

Adult↗
PubMed2004

Predictability of preimplantation genetic diagnosis of aneuploidy and translocations on prospective attempts.

The aim of this study was to determine if the outcomes of aneuploidy and translocation testing by preimplantation genetic diagnosis (PGD) at the 8-cell stage have a predictive value for new genetic diagnosis cycles. In total, 83 cycles (39 patients) undergoing PGD of translocations and 378 cycles (176 patients) of aneuploidy were included. Predictability, defined as having similar rate (+/-20%) of euploid embryos in the first and successive cycles, was found in 66% of patients undergoing aneuploidy testing. Predictability was found significantly more often in patients undergoing PGD of translocations (90%, P = 0.006). In addition, patients with 0, <30 or > or =30% euploid embryos in the first cycle were compared and groups 0 and <30% had significantly fewer euploid embryos in the second cycle (22-26%) than those of the group with > or =30% (37%) (P < 0.05). Patients who did not become pregnant after the first attempt were stimulated more aggressively than those becoming pregnant, producing significantly more embryos in the second than in the first cycle (P < 0.001). Therefore, correlation between euploidy rate and pregnancy rate could not be assessed objectively between cycles. In conclusion, the PGD results of a first cycle can predict the results of the second cycle, but this is likely to be of more value when the condition investigated is translocation rather than aneuploidy. The chance of pregnancy is usually related to the number of euploid embryos.

Abortion, Habitual↗
PubMed2003

Preimplantation genetic diagnosis and human implantation--a review.

By selecting chromosomally normal embryos for replacement, PGD for aneuploidy can (i) increase implantation rates, (ii) reduce spontaneous abortion rates, and (iii) avoid aneuploid conceptions. When eight chromosomes are analysed, a significant increase in implantation is achieved. PGD is also found to significantly reduce the incidence of spontaneous abortion and chromosomally abnormal conceptions. PGD for patients of advanced maternal age with an adequate number of embryos will improve their chances of childbirth via improved implantation and sustained gestation. PGD has also been used to help other specific groups of patients with high rates of chromosome abnormalities such as patients with recurrent spontaneous abortions, non-obstructive azoospermia, repeated IVF failure, and patients previous trisomic offspring. Recently, PGD has been performed using comparative genome hybridization, which counts all chromosomes; but time constraints require embryo cryopreservation, which reduces the potential of improved implantation

Adult↗
PubMed2002

Possible interchromosomal effect in embryos generated by gametes from translocation carriers.

BACKGROUND: The incidence of abnormal pregnancies in carriers of balanced translocations depends strictly on the chromosomes involved in the translocations. The aim of this study was to verify whether conventional aneuploidy screening could be advantageously combined with preimplantation genetic diagnosis (PGD) for translocations. METHODS: Twenty-eight carriers of Robertsonian and reciprocal translocations underwent 43 PGD cycles; specific probes were used to screen the translocation in 172 embryos generated by 35 cycles; most of these embryos were also screened for chromosomes 13, 16, 18, 21, 22 (n = 166), XY (n = 107), 1 (n = 17) and 15 (n = 88). For the remaining eight cycles (carriers of reciprocal translocations) only the chromosomes involved in common aneuploidy screening were investigated on the 40 embryos generated in vitro. RESULTS: In Robertsonian translocations, the proportion of embryos with abnormalities due to the translocation was 21%, common aneuploidies contributed 31% of total abnormalities, whereas the remaining 36% of embryos had abnormalities due to both types of chromosome. For reciprocal translocations, the chromosomes involved in the translocation were responsible for 65% of total abnormalities; only 6% of the embryos were abnormal for common aneuploidies and 16% carried abnormalities due to both the chromosomes involved in the translocation and those not related to the translocation. CONCLUSIONS: An interchromosomal effect seems to play a role in the case of Robertsonian translocations, where the relevant contribution of aneuploidy exposes the couple to an additional risk of abnormal pregnancy.

Aneuploidy↗
PubMed2001

Towards a full karyotype screening of interphase cells: 'FISH and chip' technology.

Numerical chromosome aberrations are incompatible with normal human development. Our laboratories develop hybridization-based screening tools that generate a maximum of cytogenetic information for each polar body or blastomere analyzed. The methods are developed considering that the abnormality might require preparation of case-specific probes and that only one or two cells will be available for diagnosis, most of which might be in the interphase stage. Furthermore, assay efficiencies have to be high, since there is typically not enough time to repeat an experiment or reconfirm a result prior to fertilization or embryo transfer. Structural alterations are delineated with breakpoint-spanning probes. When screening for numerical abnormalities, we apply a Spectral Imaging-based approach to simultaneously score as many as ten different chromosome types in individual interphase cells. Finally, DNA micro-arrays are under development to score all of the human chromosomes in a single experiment and to increase the resolution with which micro-deletions can be delineated.

Blastomeres↗
PubMed2001

Preimplantation genetic diagnosis of structural abnormalities.

Preimplantation genetic diagnosis (PGD) of translocations can be achieved through a variety of methods. For female carriers, a possibility is by polar body biopsy and analysis of its metaphase chromosomes using painting probes. For male carriers or female carriers with terminal breakpoints, metaphase chromosomes can also be studied by fusing blastomeres to enucleated oocytes. Otherwise, interphase analysis of the translocation can be performed using distal, subtelomeric or breakpoint spanning probes. The results obtained after PGD of translocations indicate a significant decrease in spontaneous abortions after the procedure, a good selection against unbalanced oocytes and embryos, and pregnancy rates that depend on the type of translocation involved. Balanced translocations occur in 0.2% of the neonatal population, but at a higher rate among infertile couples and patients with recurrent abortions. In a recent report, balanced translocations were found in 0.6% of infertile couples, 3.2% of couples that failed over ten IVF cycles, and 9.2% among fertile couples experiencing three or more consecutive first-trimester abortions (Hum. Reprod. 14 (1999) 2097). They were also found in 2-3.2% of males requiring ICSI (Hum. Reprod. 11 (1996) 2609; Hum. Reprod. 13 (1998) 576). PGD can be offered to carriers of balanced translocations as an alternative to prenatal diagnosis and pregnancy termination of unbalanced fetuses. In recent years, PGD for structural chromosome abnormalities has been attempted by a variety of approaches. The aims of PGD for translocations are to reduce the rate of spontaneous abortions that this population suffers and to minimize the risk of conceiving an unbalanced baby.

Abortion, Spontaneous↗
PubMed2001

Preimplantation genetic diagnosis of pericentric inversions.

Inversions are structural chromosome abnormalities that may be associated with infertility, multiple miscarriage and chromosomally unbalanced offspring. Preimplantation genetic diagnosis (PGD) with subtelomeric probes was used to select for transfer only those embryos that were normal or balanced for three pericentric inversions. In contrast to previous protocols the present procedure allows the detection of unbalanced embryos that might arise from U-recombination in the inverted region. Additionally, aneuploidy screening was carried out in two cases by a second round of fluorescent in situ hybridization (FISH) with centromeric probes. Of the three couples that underwent the procedure one became pregnant twice. The first pregnancy delivered a healthy and chromosomally normal baby and the second pregnancy is ongoing with triplets.

Adult↗
PubMed2001

Double locus analysis of chromosome 21 for preimplantation genetic diagnosis of aneuploidy.

Preimplantation genetic diagnosis (PGD) of numerical chromosome abnormalities significantly reduces spontaneous abortions and may increase pregnancy rates in women of advanced maternal age undergoing in vitro fertilization. However, the technique has an error rate of around 10% and trisomy 21 conceptions have occurred after PGD. To further reduce the risk of transferring trisomy 21 embryos to the patient, we designed a protocol that analyzes chromosome 21 twice by targeting two different loci. This protocol was applied to 388 embryos from 60 cycles of PGD of aneuploidy. The scoring criterion used was based on giving equal importance to both probe results. Of the 242 embryos diagnosed as abnormal, 125 were re-biopsied to assess the rate of false positives and false negatives of the protocol and their clinical relevance. The results of the present study showed no reduction in the overall fluorescent in situ hybridization (FISH) error rate for single cells. However, by using a different scoring criterion, the incidence of false negative can be reduced to 1.6% without missing any trisomy 21. In addition, the present study suggests that if two or more loci from the same chromosome could be simultaneously analyzed in single cells, errors caused by false monosomies could be reduced.

Aneuploidy↗
PubMed2001

Preimplantation genetic diagnosis (PGD), a collaborative activity of clinical genetic departments and IVF centres.

Preimplantation genetic diagnosis (PGD) requires the combined efforts of geneticists and workers in the field of reproductive medicine. This was studied on the basis of a questionnaire, sent to 35 members of the PGD Consortium of the European Society of Human Reproduction and Embryology (ESHRE). A reply was obtained from 20 centres. They represent the majority of activities in the field of PGD in the world. It is obvious that many of the activities (in vitro fertilisation, embryo culture and biopsy) take place in IVF units while others (counselling and diagnosis) are the responsibility of genetic diagnostic centres. The distances between both units vary considerably. In all but one centre sex determination is offered. Aneuploidy screening is offered in 13 out of 20 centres. PGD of translocations and other structural chromosome abnormalities is offered in all but one centre. The number of monogenic diseases offered varies considerably. In comparison to prenatal diagnosis PGD is more expensive. The majority of these costs are due to the IVF or ICSI procedure. The charges for PGD vary between about 600 euro and 4000 euro. In 16 out of 20 centres the parents to be must sign an informed consent form.

Aneuploidy↗
PubMed2001

Developmental ability of chromosomally abnormal human embryos to develop to the blastocyst stage.

BACKGROUND: A correlation between morphology, developmental competence and chromosome abnormalities is established. However, since absolute correlations are rare, embryo selection remains one of the most arduous tasks in assisted reproduction. This study was undertaken in order to determine which chromosomal abnormalities are compatible with development to the blastocyst stage. METHODS: Embryos diagnosed by preimplantation genetic diagnosis (PGD) as chromosomally abnormal or unsuitable for transfer were cultured to day 5 or 6. Morphology and development were observed daily. After extended culture, embryos were fixed and analysed by two rounds of FISH with the same probes used for PGD. RESULTS: Some types of numerical chromosome abnormalities do not preclude full differentiation in vitro. For instance, extensive mosaicism was detected in blastocysts and trisomic embryos reached the blastocyst stage with a frequency of 37%. Interestingly, only those monosomies compatible with first trimester development (monosomy X and 21) were detected at blastocyst stage. CONCLUSION: Even though there is a strong selection against chromosomally abnormal embryos, extended culture to day 5 or 6 cannot be used as a reliable tool to select against clinically relevant chromosome abnormalities such as trisomies.

Adult↗
PubMed2000

Selection of the most common chromosome abnormalities in oocytes prior to ICSI.

So far, all preimplantation genetic diagnosis (PGD) protocols in use produce results after the eggs have been fertilized. However, these approaches are not acceptable for patients with moral objections to the generation and discard of supernumerary zygotes or embryos. In these circumstances, only those oocytes to be replaced may be inseminated. The purpose of this study was to develop a PGD protocol to diagnose first polar bodies (PBs) prior to Intracytoplasmatic Sperm Injection (ICSI) in order to inseminate only those oocytes found to be chromosomally normal. PB biopsy was performed 1 hour after ovum pick up, and after fixation, the PBs were analysed by FISH and the eggs inseminated by ICSI no later than 7 hours after retrieval. One third (33.3%) of the PBs were aneuploid. Fifty-four normal and 12 non-resolved oocytes were injected by ICSI, of which 65% became 2-PN zygotes. Embryo transfer on day 2 was possible in all 10 patients (average maternal age 35.2+/-3.2, range 29-39 years), of which 6 became pregnant with 8 fetuses (28.6% or 8/28 transferred embryos). The results indicate that PB analysis of some common chromosome abnormalities is feasible within time limits imposed by ICSI insemination (6 hours or less).

Adult↗
PubMed2000

Analysis of chromosome abnormalities in sperm and embryos from two 45,XY,t(13;14)(q10;q10) carriers.

Robertsonian translocation t(13q14q) is studied in sperm and embryos of two couples undergoing preimplantation genetic diagnosis (PGD) in which both males are carriers of the translocation. It is already known that the chances of achieving pregnancy for a translocation carrier are directly linked to the number of normal or balanced embryos available for replacement. In our work it was found that the frequency of balanced spermatozoa was almost identical in both patients (74 and 77%), and after PGD, the frequencies of abnormal embryos caused by the translocation were also similar. Sperm chromosome analysis in translocation carriers can provide a reasonable basis for estimating a baseline of chromosome abnormalities to be found in embryos during an assisted reproductive cycle. However, individual factors not linked to the translocation can also produce other chromosome abnormalities (mosaicism, haploidy, polyploidy) and may compromise the chances of achieving a viable pregnancy.

Adult↗
PubMed2000

Outcome of preimplantation genetic diagnosis of translocations.

OBJECTIVE: To review 35 cases of preimplantation genetic diagnosis (PGD) of translocations with several methods, including telomeric probes. DESIGN: Retrospective study. SETTING: Clinical IVF laboratory. PATIENT(S): Thirty-five couples with one partner carrying a chromosomal translocation. INTERVENTION(S): PGD of translocation after polar-body or embryo biopsy. MAIN OUTCOME MEASURE(S): Pregnancy outcome. RESULT(S): Several trends were observed. First, PGD can achieve a statistically significant reduction in spontaneous abortion, from 95% to 13%. Second, the chances of achieving pregnancy are correlated with 50% or more of the embryos being chromosomally normal. Third, patients with robertsonian translocations produced fewer abnormal gametes and more pregnancies than did patients with reciprocal translocations. Fourth, a new fluorescence in situ hybridization protocol for PGD of translocations, which involves applying telomeric probes, has proved adequately reliable with a 6% average error rate. CONCLUSION(S): PGD of translocations achieves a statistically significant reduction in spontaneous abortion, both for polar-body and blastomere biopsy cases. Pregnancy outcome depended on the number of normal embryos available for transfer, with patients having <50% abnormal embryos achieving the most pregnancies. Because robertsonian translocations caused fewer abnormal embryos than reciprocal translocations, they also resulted in higher rates of implantation.

Abortion, Spontaneous↗