Cytogenetic diagnosis of "normal 46,XX" karyotypes in spontaneous abortions frequently may be misleading

Informatics enhanced SNP microarray analysis of 30 miscarriage samples compared to routine cytogenetics

Purpose

The metaphase karyotype is often used as a diagnostic tool in the setting of early miscarriage; however this technique has several limitations. We evaluate a new technique for karyotyping that uses single nucleotide polymorphism microarrays (SNP). This technique was compared in a blinded, prospective fashion, to the traditional metaphase karyotype.

Methods

Patients undergoing dilation and curettage for first trimester miscarriage between February and August 2010 were enrolled. Samples of chorionic villi were equally divided and sent for microarray testing in parallel with routine cytogenetic testing.

Results

Thirty samples were analyzed, with only four discordant results. Discordant results occurred when the entire genome was duplicated or when a balanced rearrangement was present. Cytogenetic karyotyping took an average of 29 days while microarray-based karytoyping took an average of 12 days.

Conclusions

Molecular karyotyping of POC after missed abortion using SNP microarray analysis allows for the ability to detect maternal cell contamination and provides rapid results with good concordance to standard cytogenetic analysis.

Female overweight is not associated with a higher embryo euploidy rate in first trimester miscarriages karyotyped by hysteroembryoscopy

Overweight women (body mass index ≥ 25 kg/m(2)) present an embryo euploidy rate in first trimester miscarriages similar to normoweight controls after a selective biopsy and karyotyping of embryo and/or chorion samples taken by hysteroembryoscopy.

Using FISH to increase the yield and accuracy of karyotypes from spontaneous abortion specimens

OBJECTIVE

Cytogenetic analysis of spontaneous abortions is frequently complicated by culture failure and maternal cell contamination (MCC). The objective of the study is to demonstrate that multiplex fluorescence in situ hybridization (FISH) can increase the yield and accuracy of karyotypes from spontaneous abortion specimens.

METHOD

A multiplex interphase FISH probe set was used to analyze two sample sets. (1) Uncultured tissues from 153 abortions samples with a normal 46,XX karyotype and (2) a series of 171 samples that either failed to grow or were contaminated. MCC studies were performed on 70 cultures where both karyotype and FISH indicated a normal female karyotype.

RESULTS

FISH showed 31% (53/171) of the specimens karyotyped as 46,XX were either male or abnormal; 23% (40/118) of these specimens were found to have an abnormal chromosome complement. In specimens with culture failure, FISH showed an abnormal complement in 44.4% (68/153). MCC studies showed 41.49% (29/70) cultures of maternal origin, 45.7% (32/70) fetal, 11.4% (8/70) a maternal/fetal mixture and 1 diploid mole.

CONCLUSION

Results demonstrate the utility of a simple FISH panel in increasing the detection rate of abnormal karyotypes. They also reveal the high frequency of overgrowth of maternal cells in cultured specimens from villi after embryonic loss.

Ovarian stimulation and the risk of aneuploid conceptions

OBJECTIVE

To examine the rate of aneuploidy in missed abortions in patients who conceived after FSH ovarian stimulation compared with women who conceived in a natural cycle.

DESIGN

Retrospective cohort.

SETTING

Academic reproductive endocrinology and infertility center.

PATIENT(S)

Women with karyotyping of products of conception (POC) from a missed abortion from January 1999 through August 2007. The rate of aneuploidy was compared between patients with a history of infertility who conceived naturally and patients with a history of infertility who conceived with FSH treatment.

INTERVENTION(S)

Ovarian stimulation with FSH, intrauterine insemination, and in vitro fertilization; genetic testing of POC after dilation and curettage.

MAIN OUTCOME MEASURE(S)

Embryonic karyotype.

RESULT(S)

A total of 229 pregnancies met inclusion criteria, and of these, 64% had an abnormal karyotype. The rate of aneuploidy was 63% in the study group and 70% in the control group. This difference was not statistically significant.

CONCLUSION(S)

The incidence of embryonic aneuploidy was not higher in pregnancies conceived with FSH stimulation compared with spontaneous conceptions in infertility patients. This suggests that exogenous FSH exposure does not increase the risk of aneuploidy.

Application of touch FISH in the study of mosaic tetraploidy and maternal cell contamination in pregnancy losses

PURPOSE

karyotype is a well established technique in the study of spontaneous miscarriages but is associated with selective overgrowth of maternal cells and other culture artefact (spp) such as tetraploidy, which could mask the true karyotype of the conceptus.

METHODS

328 cases of pregnancy losses were studied by karyotype and Multiplex Ligation Dependent Probe Amplification technique. Touch FISH performed in non-cultured cells was used to evaluate the ploidy complement and sex discrepancies using centromeric probes for chromosomes X, Y and 18.

RESULTS

touch FISH confirmed 13 cases of maternal contamination, identified a triploidy and a monosomy X. True tetraploidy was confirmed in 7/14 cases studied.

CONCLUSION

touch FISH protocol is extremely accurate in the distinction of genuine mosaicism from tissue culture artifacts namely in cases with suspicion of tetraploidy and can be used to confirm maternal cell contamination in cases with sex discrepancy between karyotype and MLPA.

Detection of low-level mosaicism and placental mosaicism by oligonucleotide array comparative genomic hybridization

PURPOSE

To determine the sensitivity of whole-genome oligonucleotide array comparative genomic hybridization for the detection of mosaic cytogenetic abnormalities.

METHODS

Mosaicism sensitivity was evaluated by testing artificially derived whole chromosome and segmental aneuploidies ranging from 0% to 100% abnormal and additional naturally occurring mosaic specimens.

RESULTS

Using combined dye-reversed replicates and an unfiltered analysis, oligonucleotide array comparative genomic hybridization detected as low as 10% and 20-30% mosaicism from whole chromosome and segmental aneuploidies, respectively. To investigate discrepancies between cultured and uncultured specimens, array comparative genomic hybridization was performed on DNA from additional direct product of conception specimens with abnormal karyotypes in culture. Interestingly, 5 of 10 product of conception specimens with double trisomies on cultured cell analysis had only a single trisomy by array comparative genomic hybridization and quantitative polymerase chain reaction on DNA from the uncultured direct specimen, and all harbored the more commonly observed trisomy. Thus, oligonucleotide array comparative genomic hybridization revealed previously unidentified placental mosaicism in half of the products of conception with double-aneuploid conventional karyotypes.

CONCLUSION

Oligonucleotide array comparative genomic hybridization can detect low-level mosaicism for whole chromosome ( approximately 10%) and segmental ( approximately 20-30%) aneuploidies when using specific detection criteria. In addition, careful interpretation is required when performing array comparative genomic hybridization on DNA isolated from direct specimens as the results may differ from the cultured chromosome analysis.

Array comparative genomic hybridization and flow cytometry analysis of spontaneous abortions and mors in utero samples

Background

It is estimated that 10-15% of all clinically recognised pregnancies result in a spontaneous abortion or miscarriage. Previous studies have indicated that in up to 50% of first trimester miscarriages, chromosomal abnormalities can be identified. For several decades chromosome analysis has been the golden standard to detect these genomic imbalances. A major drawback of this method is the requirement of short term cultures of fetal cells. In this study we evaluated the combined use of array CGH and flow cytometry (FCM), for detection of chromosomal abnormalities, as an alternative for karyotyping.

Methods

In total 100 spontaneous abortions and mors in utero samples were investigated by karyotyping and array CGH in combination with FCM in order to compare the results for both methods.

Results

Chromosome analysis revealed 17 abnormal karyotypes whereas array CGH in combination with FCM identified 26 aberrations due to the increased test success rate. Karyotyping was unsuccessful in 28% of cases as compared to only two out of hundred samples with inconclusive results for combined array CGH and FCM analysis.

Conclusion

This study convincingly shows that array CGH analysis for detection of numerical and segmental imbalances in combination with flow cytometry for detection of ploidy status has a significant higher detection rate for chromosomal abnormalities as compared to karyotyping of miscarriages samples.

Chromosomal abnormalities in miscarriages after different assisted reproduction procedures

About 10-15% of all recognised pregnancies end in spontaneous abortion and around 60% of these show a chromosomal abnormality. The finding of an abnormal karyotype allows one to avoid unnecessary and controversial testing and treatment, providing accurate reproductive and genetic counselling to the couple. Consequently, chromosome study of products of conception (POC) is routinely performed in our Institute, starting from 2002. Cytogenetic analysis on spontaneous metaphases, obtained using direct method, was successfully performed on a total of 277 cases: 133 from patients who underwent assisted reproductive technology (ART) and 144 samples from infertile couples that had natural conceptions (NC). An abnormal karyotype was observed in 84 (63.2%) cases after ART and in 103 (71.5%) after NC demonstrating that the ART group doesn't seem subjected to a higher cytogenetic risk due to the application of technical procedures and higher than the expected risk in the fertile population. Moreover we did not observe a significant difference in the incidence of chromosome anomalies between intracytoplasmic sperm injection (ICSI) (61.5%) and in vitro fertilisation (IVF) (54.5%). However, in the ICSI with testicular sperm extraction (ICSI-TESE) group, 80% of the cases were abnormal with 50% showing triploid/tetraploid karyotypes. Chromosomal abnormalities were present in 54.5% of miscarriages which occurred after ICSI with cryo-preserved oocytes (cryo-ICSI) and in 85.7% after intra-uterine insemination (IUI). To our knowledge this study analysed the largest number of POCs after ART and NC in an infertile population. Moreover, for the first time the cytogenetic results of POC from different ART procedures were included.

Cytogenetic testing of anembryonic pregnancies compared to embryonic missed abortions

PURPOSE

The objective of this study is to determine the rate of abnormalities detected by cytogenetic testing of first trimester miscarriages, in patients with and without an embryonic pole seen on ultrasound.

MATERIALS AND METHODS

A retrospective study of 272 D&Cs for missed abortions in an academic infertility practice from 1999 to 2006. Karyotype results were compared with transvaginal ultrasound findings. Chi-squared analysis was used with a P < 0.05 for significance.

RESULTS

There was a high rate of abnormal karyotypes in all miscarriages (65%). Rates of abnormal karyotypes were 58% and 68% in cases with anembryonic gestations and those with a fetal pole seen, respectively (P > 0.05).

CONCLUSION

The high rate of abnormalities detected in both groups suggests that useful results can be obtained from chromosomal testing of the POC regardless of ultrasound findings. Further studies on the prognostic value and cost effectiveness of chromosomal testing are needed.

Testing for maternal cell contamination in prenatal samples: a comprehensive survey of current diagnostic practices in 35 molecular diagnostic laboratories

The potential presence of maternal cell contamination (MCC) in chorionic villus or amniotic fluid samples poses a serious preanalytical risk for prenatal misdiagnosis. The aim of this study was to identify current diagnostic practices in the absence of comprehensive practice guidelines. Thirty-five clinical molecular laboratories that conduct prenatal testing agreed to participate in a clinical practice survey. The survey included questions about sample requirements, test indications, assay type, test performance and limitations, criteria and management of uninformative test results, reporting, and billing. Sixty percent of participating laboratories performed testing on direct and cultured amniotic fluid, whereas forty percent tested cultured cells only. Most also accepted chorionic villus samples. Although MCC testing of fetal samples is recommended in guidelines by the American College of Medical Genetics, only 60% of surveyed laboratories performed it without exception. Commercially available assays were used by 75% of participating laboratories, and at least five identity markers were evaluated at 87% of the laboratories. The reported lower limit of MCC detection ranged from 1 to 20% but was not determined in all laboratories. MCC testing was performed in the majority of molecular diagnostic laboratories, but guidelines for standardization are needed to ensure optimal and accurate prenatal patient care.

Profile of chromosomal aberrations in different gestational age spontaneous abortions detected by comparative genomic hybridization

OBJECTIVE

To determine the frequency and type of chromosomal aberrations in different gestational age spontaneous abortions.

STUDY DESIGN

In the study, 106 spontaneous abortions (SAs) were studied by comparative genomic hybridization.

RESULTS

The frequency of detected chromosomal aberrations was 37.7%. Numerical chromosomal aberrations were disclosed in 82.5% of the aberrant cases, while structural chromosomal aberrations-in 17.5%. Highest frequency of aberrations was detected in the blighted ovum specimens (62.5%) compared to missed and second trimester SAs (respectively, 36.0% and 34.8%). With regard to structural aberrations, the difference in the frequencies between blighted ovum specimens and second trimester SAs nearly reached statistical significance (p=0.0847). However, due to the low number of blighted ovum specimens analyzed (n=8), this result should be interpreted with due caution. The most frequently affected chromosomal arms were Xp and Xq (13.7% of aberrant chromosomal arms, each), followed by 16p (8.4%), 16q (8.4%), 15q (4.2%) and 19q (4.2%).

CONCLUSIONS

We describe for the first time a profile of chromosomal aberrations in SAs from different gestational ages, detected by CGH. Our results showed highest frequency of chromosome aberrations in blighted ovum specimens compared to other types of spontaneous abortions, higher rate of structural aberrations than reported before (17.5%) and some aberrations that so far were not found by CGH.

Preimplantation genetic diagnosis significantly reduces pregnancy loss in infertile couples: a multicenter study

OBJECTIVE

The inicidence of miscarriage is correlated with maternal age. The majority of miscarriages are chromosomally abnormal. The purpose of this study was to determine in a large population of infertility patients (>2000 cycles) if preimplantation genetic diagnosis (PGD) reduced the rate of spontaneous abortions.

DESIGN

Multicenter retrospective controlled study.

SETTING

One hundred IVF centers referring samples to a reference PGD laboratory.

PATIENT(S)

Infertile women.

INTERVENTION(S)

The spontaneous abortion rate after PGD was retrospectively compared to non-PGD cycles from the 2002 American Society for Reproductive Medicine-Society for Assisted Reproduction Technology report on IVF cycles.

MAIN OUTCOME MEASURE(S)

Spontaneous abortions and trisomic offspring rates.

RESULT(S)

The study included 2,279 cycles of PGD. The pregnancy rate per retrieval was 26.7% (average age 39.6). The mean pregnancy loss for the PGD group (0.167) was significantly lower than for the general IVF group (0.215) (P<.001). After PGD, the spontaneous abortion rate was 14.1% for ages 35-40, and 22.2% for women over 40, compared to 19.4% (P=.03) and 40.6% (P<.001), respectively, in controls. The clinical error rate of PGD (1.2%) was significantly lower than expected (4.7%) (P<.001).

CONCLUSION(S)

The data suggests that PGD significantly reduces the risk of spontaneous abortions in women undergoing IVF and PGD, particularly in women over 40. In addition, PGD may also reduce the risk of trisomic offspring.

Detecting sex chromosome anomalies and common triploidies in products of conception by array-based comparative genomic hybridization

OBJECTIVES

In recent years, array-based comparative genomic hybridization (array CGH) has moved to the forefront of molecular cytogenetics with its ability to rapidly characterize chromosome abnormalities at resolutions much higher than routine chromosome banding. However, array CGH, like all CGH procedures, has heretofore been deemed unable to detect ploidy, a major cause of fetal demise and spontaneous miscarriage.

METHOD

We recently developed a CGH microarray that is designed for detecting aneuploidy and unbalanced chromosome rearrangements. Here, we introduce the use of a Klinefelter male cell line (47,XXY) as a control for array CGH analyses on products of conception (POCs).

RESULTS

This approach facilitates the detection of common trisomies and monosomies of the sex chromosomes by reducing the analysis to the identification of single copy gains or losses. Furthermore, in a blinded study, careful interpretation of the microarray results with particular attention to the sex chromosome ratios between the patient sample and the control allowed for the detection of some common triploidies.

CONCLUSION

These results suggest that using a chromosomally abnormal cell line in array CGH analysis can be applied to other CGH platforms and that array CGH, when properly performed and analyzed, is a powerful tool that can detect most chromosomal abnormalities observed in a clinical setting including some polyploidies.

High-throughput analysis of chromosome abnormality in spontaneous miscarriage using an MLPA subtelomere assay with an ancillary FISH test for polyploidy

Chromosome analysis of spontaneous miscarriages is clinically important but is hampered by frequent tissue culture failure and relatively low-resolution analysis. We have investigated replacement of conventional karyotype analysis with a quantitative subtelomere assay performed on uncultured tissue samples, which is based on Multiplex Ligation-Dependent Probe Amplification. This assay is suitable for this purpose as approximately 98% of all observed karyotype abnormalities in spontaneous miscarriages involve copy-number change to one or more subtelomere regions. A pilot study has compared karyotyping and subtelomere analysis on 78 samples. Extensive tissue necrosis accounted for failure of both karyotyping and subtelomere testing in four (5.1%) samples. Excluding these, there were no (0/74) subtelomere test failures compared to 9.5% (7/74) karyotype failures. Twenty-two (30%) whole chromosome aneuploidies and five (6.8%) structural abnormalities were detected using the subtelomere assay. With the exception of three cases of triploidy, all karyotype abnormalities were detected by the subtelomere assay. Following on from this study, a further 100 samples were tested using the subtelomere assay in conjunction with a simple ancillary FISH test using uncultured cells to exclude polyploidy in the event of a normal subtelomere assay result. Except for three necrotic samples, tests results were obtained for all cases revealing 18 abnormalities including one case of triploidy. Taking into consideration the high success rate for the combined MLPA and FISH test results, and the very significant additional advantages of cost-effective, high-throughput batching, and automated, objective analysis, this approach greatly facilitates routine investigation of chromosome abnormalities in spontaneous miscarriage.

Double trisomy in spontaneous miscarriages: cytogenetic and molecular approach

BACKGROUND

Although single trisomy is the most common chromosomal abnormality observed within first trimester spontaneous abortions (SA) (>50%), double trisomy (DT) ranges from 0.21 to 2.8% in the literature. Since little is known about mechanisms underlying DT, we report the results of our experience with 517 SA, establishing parental origin and cell stage of non-disjunction when possible in DT cases, and making a revision of those previously reported.

METHODS

Cytogenetic analysis was performed in all aborted specimens. Quantitative fluorescent PCR (QF-PCR) and multiplex ligation-dependent probe amplification (MLPA) were performed in DT cases in order to assess parental origin and stage of error of aneuploidy in addition to its reliability in detecting aneuploidies.

RESULTS

Karyotyping was successful in 321 miscarriages; the rate of DT was 2.18%. Among the seven DT cases reported, three new combinations were found. Maternal origin was established for all DT SA analysed. Meiotic stage of error was presumed meiosis I (MI) for 48,XX+15+22 and 48,XX+8+21, meiosis II (MII) for 48,XXX+18, and MII and MI respectively for 48,XY+18+22. Molecular results agreed with cytogenetic results.

CONCLUSIONS

Similar maternal age-related mechanisms could be implicated in both single and double trisomy. Molecular techniques could be useful in diagnosing not only single but multiple aneuploidy and determining its origin. This will improve our knowledge about mechanisms underlying human aneuploidy, and enable appropriate genetic counselling.

Is cytogenetic diagnosis of 46,XX karyotype spontaneous abortion specimens erroneous? Fluorescence in situ hybridization as a confirmatory technique

AIM

Performing the standard cytogenetic technique on spontaneous abortion material is still a valuable tool, but finding a normal 46,XX karyotype can confuse investigators and lead to a problem in diagnosis. This is mainly because it is possible for the female or male conceptus to retain contaminating maternal cells. To address this possibility, we used fluorescence in situ hybridization technique (FISH). X (DXZ1: p11.1-q11.1 region) and Y (DYZ3: p11.1-q11.1 region) chromosome alpha-satellite probes were employed to confirm the karyotypes previously diagnosed as 46,XX by our cytogenetic laboratory, or to verify the occurrence of 'Y chromosome component'.

METHODS

Besides conventional long-term tissue cultures and G-bands by trypsin using Giemsa (GTG) bandings, FISH analyses were also performed.

RESULTS

A total of 134 spontaneous abortion specimens (singleton gestations) were referred for cytogenetic evaluation, of which 125 specimens were successfully karyotyped. Of these, 20.8% (26/125) had chromosome aberrations; 88.5% (23/26) of these aberrations were numerical and 11.5% (3/26) were structural. The most prevalent numerical anomalies were trisomies 15, 16 and 21, tetraploidies, triploidies and monosomy X. FISH results were obtained for 45 out of 92 cases with 46,XX, of which 2 (4.4%) showed XY signals.

CONCLUSIONS

For accurate cytogenetic evaluation of spontaneous abortion materials, an additional technique such as FISH is required in order to confirm the cytogenetic results or to provide an estimate of the error rate in the analysis of miscarriages.

Comparative genomic hybridization analysis of spontaneous abortion

OBJECTIVES

To evaluate the feasibility and superiority of comparative genomic hybridization (CGH) in the genetic analysis of spontaneously aborted tissues.

METHODS

38 conceptuses from early failed pregnancies were studied, of which, 27 samples were fresh and 11 were old. Each sample was divided into two parts, one part for conventional cytogenetic analysis and the other for CGH analysis.

RESULTS

All 38 spontaneously aborted tissues were analyzed successfully by the CGH approach, but only 31 samples received results from the cytogenetic karyotype analysis, while 7 other tissues failed to get data due to failure in tissue culturing. Among the specimen successfully analyzed by both approaches, 90% (28 out of 31) obtained identical results, and 14 aneuploidies were found. The only structural chromosome aberration in this series, 46, XY, del(3) (q22-24), was found using the CGH approach, which appeared as a normal male karyotype on the chromosomal metaphase spread. Also, two cases indicated triploidies under cytogenetic analysis but appeared to be normal on the CGH profile. In addition, among the seven samples of tissue culture failure, CGH identified three to be aneuploidies.

CONCLUSION

The CGH analysis accurately identifies chromosomal unbalanced abnormalities related to spontaneous abortions with low failure rate.

A mathematical model for evaluation of maternal cell contamination in cultured cells from spontaneous abortions: significance for cytogenetic analysis of prenatal selection factors

OBJECTIVE

To develop a mathematical model for more precise estimation of the incidence of chromosomal abnormalities and the sex ratio among spontaneous abortions masked by maternal cell contamination.

DESIGN

Retrospective analysis.

SETTING

Academic medical center.

PATIENT(S)

One hundred twelve samples of spontaneous abortion with a "46,XX" karyotype and 97 parents with aborted embryos.

INTERVENTION(S)

The presence of Y chromosome DNA in native tissues of "46,XX" spontaneous abortions was detected by amelogenin locus analysis. Detection of aneuploidies in noncultured tissues of "46,XX" abortions was performed by microsatellite DNA analysis and confirmed by fluorescence in situ hybridization.

MAIN OUTCOME MEASURE(S)

Accuracy of cytogenetic evaluation of spontaneous abortions.

RESULT(S)

Y chromosome DNA was revealed in 16% of the embryos with a "46,XX" karyotype. According to the mathematical model proposed, the frequency of chromosomal abnormalities in a sample of 478 abortions increased from 54.6% to 60.3%, and the sex ratio in embryos with normal karyotype changed from 0.66 to 1.02. The experimental validation of the model has shown that the observed and expected incidences of chromosomal abnormalities in "46,XX" abortions were in good agreement.

CONCLUSION(S)

Maternal cell contamination clearly affects the incidence of registered chromosomal abnormalities and the sex ratio in spontaneous abortions. Correction for maternal cell contamination should be taken into account before invoking biological explanations of sex ratio bias and might be useful to include in diagnostic reporting.

Treatment of antiphospholipid antibody syndrome (APS) in pregnancy: a randomized pilot trial comparing low molecular weight heparin to unfractionated heparin

OBJECTIVE

To compare low molecular weight heparin (LMWH), specifically dalteparin, to unfractionated heparin (UFH) for the treatment of antiphospholipid antibody syndrome (APS) in pregnancy.

METHODS

In a tertiary referral centre, 28 women met the 1999 International Consensus Criteria for APS, based on their obstetrical history and APS serology. The women were randomized, using a random numbers table with blocks of 12, to receive either prophylactic dosing of dalteparin or UFH starting either preconceptionally or early in pregnancy. All women also received low-dose acetylsalicylic acid, started preconceptionally. The primary outcome was a live birth. The secondary outcomes were maternal and fetal complications.

RESULTS

Of the 14 women who received the LMWH, dalteparin, and the 14 women who received UFH, 1 woman in each group did not conceive. Nine of the 13 women (69%) given dalteparin had a successful pregnancy (95% confidence interval [CI], 39-91%), compared to 4 out of the 13 women (31%) in the UFH group (95% CI, 9-61%). Nine women in total had spinal or epidural anaesthesia, and there were no complications overall.

CONCLUSION

Dalteparin may be an effective alternative to UFH for treatment of APS in pregnancy. A multicentre randomized trial is needed to determine benefit-to-risk ratios for the use of dalteparin and UFH to treat this high-risk obstetrical condition. Pharmacokinetic and pharmacodynamic studies are also recommended to maximize therapeutic response and minimize toxicity.

Anti-thyroid Antibodies and Antiphospholipid Syndrome: Evidence of Reduced Fecundity and of Poor Pregnancy Outcome in Recurrent Spontaneous Aborters

PROBLEM

To determine the presence of anti-thyroid antibodies in patients with primary antiphospholipid syndrome (APS) [antiphospholipid antibodies (aPL) + recurrent spontaneous abortion (RSA)], compare APS alone with APS and thyroid autoimmunity for fecundity and for pregnancy outcome.

METHOD OF STUDY

A total of 203 non-pregnant women affected with primary APS were evaluated for anti-thyroid antibodies; 162 non-pregnant women affected with RSA and thyroid autoimmunity alone served as controls.

RESULTS

Anti-thyroid antibodies were found in 27% of APS patients studied. Patients with aPL alone had higher percentages of spontaneous pregnancies (P < 0.0001) and live births (P = 0.0003), when compared with patients positive for anti-thyroid antibodies alone or with aPL.

CONCLUSIONS

Thyroid autoimmunity is frequently present in APS recurrent aborters and is often associated with either reduced fecundity or with poor pregnancy outcome. Thyroid antibodies should always be evaluated in women with RSA including those with aPL.

Comparative genomic hybridization-array analysis enhances the detection of aneuploidies and submicroscopic imbalances in spontaneous miscarriages

Miscarriage is a condition that affects 10%-15% of all clinically recognized pregnancies, most of which occur in the first trimester. Approximately 50% of first-trimester miscarriages result from fetal chromosome abnormalities. Currently, G-banded chromosome analysis is used to determine if large-scale genetic imbalances are the cause of these pregnancy losses. This technique relies on the culture of cells derived from the fetus, a technique that has many limitations, including a high rate of culture failure, maternal overgrowth of fetal cells, and poor chromosome morphology. Comparative genomic hybridization (CGH)-array analysis is a powerful new molecular cytogenetic technique that allows genomewide analysis of DNA copy number. By hybridizing patient DNA and normal reference DNA to arrays of genomic clones, unbalanced gains or losses of genetic material across the genome can be detected. In this study, 41 product-of-conception (POC) samples, which were previously analyzed by G-banding, were tested using CGH arrays to determine not only if the array could identify all reported abnormalities, but also whether any previously undetected genomic imbalances would be discovered. The array methodology detected all abnormalities as reported by G-banding analysis and revealed new abnormalities in 4/41 (9.8%) cases. Of those, one trisomy 21 POC was also mosaic for trisomy 20, one had a duplication of the 10q telomere region, one had an interstitial deletion of chromosome 9p, and the fourth had an interstitial duplication of the Prader-Willi/Angelman syndrome region on chromosome 15q, which, if maternally inherited, has been implicated in autism. This retrospective study demonstrates that the DNA-based CGH-array technology overcomes many of the limitations of routine cytogenetic analysis of POC samples while enhancing the detection of fetal chromosome aberrations.

Improved accuracy of hysteroembryoscopic biopsies for karyotyping early missed abortions

OBJECTIVE

To assess the potential of direct embryo and chorion biopsies obtained by hysteroembryoscopy for karyotyping early missed abortions.

DESIGN

Clinical prospective descriptive study.

SETTING

Instituto Valenciano de Infertilidad, Valencia, Spain.

PATIENT(S)

Sixty-eight women (71 gestational sacs) with missed abortions. The gestational age on ultrasound was 6.3 weeks (range, 4-10 weeks).

INTERVENTION(S)

Transcervical hysteroembryoscopy before curettage.

MAIN OUTCOME MEASURE(S)

Comparison between the cytogenetic results from hysteroembryoscopic biospies and those of the curettage material.

RESULT(S)

Hysteroembryoscopic biopsies could be taken in 97.2% of the gestational sacs. Direct embryo and chorion biopsies were suitable for chromosomal analysis. Selective samples identified misdiagnoses of the conventional curettage karyotype due to maternal contaminating tissues in 22.2% of the cases. Direct hysteroembryoscopic biopsies also enabled the diagnosis of a true placental mosaicism and the study of the individual karyotype of each gestational sac in bizygotic twin missed abortions.

CONCLUSION(S)

In early missed abortions, karyotypes from direct hysteroembryoscopic biopsies were more accurate than those from the curettage material. The finding of a 46,XX karyotype in the curettage material is not a reliable result.

Tissue sampling technique affects accuracy of karyotype from missed abortions

PURPOSE

To determine if careful specimen selection and washing of tissue from first trimester missed abortion products of conception specimens increases the sensitivity of routine cytogenetics in detecting aneuploidy.

METHODS

Retrospective review of cytogenetics results from tissue from dilation and curettage for missed abortion in a university fertility practice between 1998 and 2001. A technique of careful selection and washing of the specimen was implemented in July 1999. Results from before (n = 15) and after (n = 41) this change were compared. Cytogenetics reports from other physicians using the same laboratory were used for comparison (n = 59).

RESULTS

The percentage of 46XX results was significantly decreased in the test group when compared to historical and community controls: 29% vs. 73% and 56% respectively. The percentage of aneuploid results was significantly higher in the test group at 61% vs. 7% and 36% in the historical and community controls respectively.

CONCLUSION

Thorough separation and cleaning of villi prior to sending missed abortion specimens significantly increases sensitivity of conventional cytogenetics for detecting aneuploidy by decreasing maternal contamination.

Peripheral-type benzodiazepine receptor (PBR) gene amplification in MDA-MB-231 aggressive breast cancer cells

Recent studies using human breast cancer cell lines, animal models, and human tissue biopsies have suggested a close correlation between the expression of the peripheral-type benzodiazepine receptor (PBR) and the progression of breast cancer. This study investigates the genetic status of the PBR gene in two human breast cancer cell lines: MDA-MB-231 cells, which are an aggressive breast cancer cell line that contains high levels of PBR, and MCF-7 cells, which are a nonaggressive cell line that contains low levels of PBR. Both DNA (Southern) blot and fluorescence in situ hybridization analyses indicate that the PBR gene is amplified in MDA-MB-231 relative to MCF-7 cells. These data suggest that PBR gene amplification may be an important indicator of breast cancer progression.

Cytogenetic analysis of trophoblasts by comparative genomic hybridization in embryo-fetal development anomalies

Cytogenetic studies of spontaneous abortions or intrauterine fetal death depend on conventional tissue culturing and karyotyping. This technique has limitations such as culture failure and selective growth of maternal cells. Fluorescent in situ hybridization (FISH) using specific probes permits diagnosis of aneuploidies but is limited to one or a few chromosomal regions. Comparative genomic hybridization (CGH) provides an overview of chromosomal gains and losses in a single hybridization directly from DNA samples. In a prospective study, we analyzed by CGH trophoblast cells from 21 fetuses in cases of spontaneous abortions, intrauterine fetal death or polymalformed syndrome. Six numerical chromosomal abnormalities including one trisomy 7, one trisomy 10, three trisomies 18, one trisomy 21 and one monosomy X have been correctly identified by CGH. One structural abnormality of the long arm of chromosome 1 has been characterized by CGH. One triploidy and two balanced pericentromeric inversions of chromosome 9 have not been identified by CGH. Sexual chromosomal constitutions were concordant by both classical cytogenetic technique and CGH. Contribution of trophoblast analysis by CGH in embryo-fetal development anomalies is discussed.

Cytogenetic analyses of culture failures by comparative genomic hybridisation (CGH)-Re-evaluation of chromosome aberration rates in early spontaneous abortions

Comparative genomic hybridisation (CGH) represents an alternative molecular-cytogenetic technique capable of detecting chromosomal imbalances by reverse fluorescence in situ hybridisation. As the technique uses genomic DNA for assessment it does not rely on metaphase chromosomes in the test material and thus circumvents technical problems associated with tissue culturing. In the present study, we applied CGH to identify chromosome anomalies in 60 spontaneous abortions of the first trimester, that had failed to grow in culture. In 57 out of 60 cases CGH analyses were successful. The overall aneuploidy rate detected was 72%. Trisomy was the predominant chromosome anomaly accounting for 68.0% of abnormal abortions, followed by triploidy (17.1%) and monosomy X (9.8%). An unbalanced structural rearrangement was found in one (2.4%) abortion. Most frequently involved in trisomies were chromosomes 16 (32.1%), 7 and 22 (10.7% each), 4, 13, 15, and 21 (7.2 % each). Three triploid cases and one complete mole were detected by microsatellite analysis as supplementary method. CGH data on culture failures were compared with data derived from 4693 successfully karyotyped first trimester spontaneous abortions, resulting in a chromosome aberration rate of 64.8%. The distribution of the different chromosome anomalies was similar with the exception of a higher rate of trisomies 7 and of XYY-triploidies in the culture failures. Based on our data we suggest that the genetic contribution to pregnancy loss is still underestimated. Investigating abortion tissues hitherto unassessed by conventional methods, we suggest that the contribution of chromosome aberrations to first trimester pregnancy loss is nearly 70%.

Microsatellite analysis reveals a high incidence of maternal cell contamination in 46,XX products of conception consisting of villi or a combination of villi and membranous material

OBJECTIVE

With the use of microsatellite analysis, we sought to determine the incidence of maternal cell contamination in 46,XX products of conception consisting of villi or a combination of villi and membranous material.

STUDY DESIGN

Deoxyribonucleic acid from cultured fibroblasts of 46,XX products of conception specimens and a corresponding maternal blood sample were obtained from 31 women. Maternal and fetal genotypes for several highly polymorphic microsatellite markers were compared.

RESULTS

Maternal cell contamination was present in 26 (89.7%) of the 29 products of conception specimens from which conclusive results were obtained. The contamination appeared to completely obscure the fetal material in 24 of these specimens.

CONCLUSIONS

A significant proportion of 46,XX karyotypes from products of conception represents maternal cell contamination. When maternal cells rather than fetal cells are karyotyped, no information is gained regarding the chromosome constitution of the abortus, and genetic counseling regarding recurrence risks for future pregnancies may be inaccurate. Thus laboratories should exercise caution when reporting normal female karyotypes on products of conception and should consider using microsatellite analysis to determine whether 46,XX results are truly representative of the fetal karyotype.

Diagnosis of aneuploidy in archival, paraffin-embedded pregnancy-loss tissues by comparative genomic hybridization

OBJECTIVE

To evaluate the detection of aneuploidy in archival tissues from miscarriages by a method that uses microdissection and DNA extraction of villus cells from paraffin blocks, followed by universal DNA amplification and comparative genomic hybridization (CGH).

DESIGN

Retrospective analysis.

SETTING

Academic medical center.

PATIENT(S)

Nine archival tissues from cases of spontaneous abortion with trisomy 16 (two cases), trisomy 21 (three cases), trisomy 22 (two cases), triploidy (one case), and monosomy X (one case).

INTERVENTION(S)

Villus DNA was extracted from microdissected, formalin-fixed, paraffin-embedded tissues. Aneuploidy was detected by CGH after universal amplification of the DNA with the use of degenerate oligonucleotide-primed polymerase chain reaction.

MAIN OUTCOME MEASURE(S)

Detection of aneuploidy in archival pregnancy-loss tissues using CGH.

RESULT(S)

In all nine cases, DNA was successfully extracted from the microdissected tissues and was of sufficient quantity and quality for evaluation by CGH. In six of nine cases, the chromosomal abnormality detected by conventional cytogenetic analysis was identified by CGH: trisomy 16 (2/2), trisomy 21 (3/3), and trisomy 22 (1/2). One case of each of the following was not detectable: triploidy (1/1), monosomy X (1/1), and trisomy 22 (1/2).

CONCLUSION(S)

We propose CGH as a method for determination of aneuploidy in pregnancy-loss archival tissues when conventional cytogenetic analysis is unsuccessful or when it was not performed when fresh tissue was available.

Comparative genomic hybridization: a new tool for reproductive pathology

OBJECTIVE

To demonstrate the effectiveness of comparative genomic hybridization (CGH) for analysis of reproductive pathology specimens in clinical cytogenetics laboratories.

DESIGN

A total of 856 CGH analyses were performed on various placental and fetal tissues derived from 368 specimens of spontaneous abortions and on placentas from 219 pregnancies with live-born infants. The live-born infants were clinically evaluated as normally developed, with either a normal birth weight or with intrauterine growth restriction; some live-born infants had an abnormal prenatal triple screen with normal cytogenetic results on amniotic fluid cell cultures.

RESULTS

Comparative genomic hybridization analysis was successfully performed on 856 samples from spontaneously aborted specimens and term placentas. Failure of analysis occurred in 1.6% of samples and was due to an insufficient amount of tissue for DNA extraction. Comparative genomic hybridization identified aneuploidy in 53% of spontaneous abortion samples and 3.1% of term placentas.

CONCLUSIONS

Comparative genomic hybridization analysis is a useful clinical tool for detection of aneuploidy in placental and fetal tissues. It provides a genome-wide screen while eliminating tissue culture failures, culture artifacts, and maternal cell contamination. We present practical guidelines for interpreting CGH profiles derived from human reproductive specimens.

Comparative genomic hybridization in combination with flow cytometry improves results of cytogenetic analysis of spontaneous abortions

More than 50% of spontaneous abortions (SAs) have abnormal chromosomes; the most common abnormalities are trisomy, sex chromosome monosomy, and polyploidy. Conventional cytogenetic analysis of SAs depends on tissue culturing and is associated with a significant tissue culture failure rate and contamination by maternally derived cells. Comparative genomic hybridization (CGH), in combination with flow cytometry (FCM), can detect numerical and unbalanced structural chromosomal abnormalities associated with SAs while avoiding the technical problems associated with tissue culture. Routine cytogenetic and CGH analysis was performed independently on tissue from 301 SAs. Samples shown to be chromosomally balanced by CGH were analyzed by FCM to determine ploidy. Of 253 samples successfully analyzed by both approaches, there was an absolute correlation of results in 235 (92.8%). Of the 18 cases with discrepancies between cytogenetic and CGH/FCM results, an explanation could be found in 17. Twelve samples produced a 46,XX karyotype by cytogenetics, whereas CGH/FCM demonstrated aneuploidy/polyploidy or a male genome, indicating maternal contamination of the tissue cultures. In two cases, where tetraploidy was demonstrated by cytogenetics and diploidy by FCM, tissue culture artifact is implied. In three cases, CGH demonstrated an aneuploidy, and cytogenetics demonstrated hypertriploidy. In one unexplainable case, aneuploidy demonstrated by CGH could not be detected by repeat CGH analysis, conventional cytogenetic, or FISH analysis. These results demonstrate that CGH supplemented with FCM can readily identify chromosomal abnormalities associated with SAs and, by avoiding maternal contamination and tissue culture artifacts, can do so with a lower failure rate and more accuracy than conventional cytogenetic analysis.