Comparative genomic hybridization: a new approach to screening for intrauterine complete or mosaic aneuploidy

The Landscape of Point Mutations in Human Protein Coding Genes Leading to Pregnancy Loss

Pregnancy loss is the most frequent complication of a pregnancy which is devastating for affected families and poses a significant challenge for the health care system. Genetic factors are known to play an important role in the etiology of pregnancy loss; however, despite advances in diagnostics, the causes remain unexplained in more than 30% of cases. In this review, we aggregated the results of the decade-long studies into the genetic risk factors of pregnancy loss (including miscarriage, termination for fetal abnormality, and recurrent pregnancy loss) in euploid pregnancies, focusing on the spectrum of point mutations associated with these conditions. We reviewed the evolution of molecular genetics methods used for the genetic research into causes of pregnancy loss, and collected information about 270 individual genetic variants in 196 unique genes reported as genetic cause of pregnancy loss. Among these, variants in 18 genes have been reported by multiple studies, and two or more variants were reported as causing pregnancy loss for 57 genes. Further analysis of the properties of all known pregnancy loss genes showed that they correspond to broadly expressed, highly evolutionary conserved genes involved in crucial cell differentiation and developmental processes and related signaling pathways. Given the features of known genes, we made an effort to construct a list of candidate genes, variants in which may be expected to contribute to pregnancy loss. We believe that our results may be useful for prediction of pregnancy loss risk in couples, as well as for further investigation and revealing genetic etiology of pregnancy loss.

Prenatal diagnosis of a distal 3p deletion associated with fetoplacental chromosomal discrepancy and confined placental mosaicism detected by array comparative genomic hybridization

OBJECTIVE

This study is aimed at prenatal diagnosis of a distal 3p deletion associated with fetoplacental chromosomal discrepancy and confined placental mosaicism, and providing evidence for the limitation of array comparative genomic hybridization (aCGH) on placental tissues for molecular cytogenetic characterization of prenatally detected aneuploidy.

CASE REPORT

A 30-year-old woman underwent amniocentesis at 18 weeks of gestation because of maternal anxiety. Results of amniocentesis revealed a distal deletion of chromosome 3p. A malformed female fetus was delivered at 20 weeks of gestation with brachycephaly and facial dysmorphisms, and a cytogenetic analysis of the cord blood revealed a karyotype of 46,XX,del(3)(p26.1),inv(9)(p12q13). A whole-genome aCGH on uncultured cord blood and placental tissue was performed. The aCGH on cord blood revealed a 7.4-Mb deletion at 3p26.3-p26.1. However, the aCGH on placental tissue revealed a 32.42-Mb gene dosage increase at 3p26.1-p22.1 and a 26.28-Mb gene dosage increase at 1p36.33-p36.11 in addition to a 7.4-Mb deletion at 3p26.3-p26.1, indicating confined placental mosaicism for partial trisomy 3p (3p26.1→p22.1) and mosaicism for partial trisomy 1p (1p36.33→p36.11). The 7.4-Mb deleted region of 3p26.3-p26.1 contained the following genes: CHL1, CNTN4, CRBN, LRRN1, and ITPR1.

CONCLUSION

Fetal tissue and amniocytes offer more reliable resources for aCGH characterization of prenatally detected aneuploidy compared with placental tissues. A molecular cytogenetic evaluation of prenatally detected aneuploidy using placental tissue should raise concerns of confined placental mosaicism and fetoplacental chromosomal discrepancy.

Improved efficiency of microsurgical enucleated tripronuclear zygotes development and embryonic stem cell derivation by supplementing epidermal growth factor, brain-derived neurotrophic factor, and insulin-like growth factor-1

Human embryonic stem cells (hESCs) hold great promise for future clinical cell therapies because of their unique potential to differentiate into all human cell types. However, the destruction of normal fertilized embryos and the derivation of hESCs for research has resulted in polarized ethical debates, with most of the controversy centered on embryo destruction. Therefore, due to less ethical controversy surrounding them, abnormal fertilized zygotes that are usually discarded are a potential feasible resource for the derivation of hESCs. Microsurgery on human polyspermic zygotes can contribute to the derivation of hESCs, but the efficiency is much lower. Here, we reported a culture system to enhance the developmental competence of such microsurgical human polyspermic zygotes by EGF-BDNF-IGF-1 combination, which eventually resulted in the increased derivation efficiency of hESCs from them. We found that the developmental efficiency of microsurgical enucleated tripronuclear (3PN) embryos cultured with the EGF-BDNF-IGF-1 combination was significantly increased compared with the control group. More importantly, when the microsurgical enucleated 3PN embryos were cultured in medium supplemented with EGF-BDNF-IGF-1, the frequency ratio of chromosome abnormality was reduced. Our present study will facilitate the development of hESC line derivation in subsequent studies and also provide an additional choice for infertile couples.

Comparable low-level mosaicism in affected and non affected tissue of a complex CDH patient

In this paper we present the detailed clinical and cytogenetic analysis of a prenatally detected complex Congenital Diaphragmatic Hernia (CDH) patient with a mosaic unbalanced translocation (5;12). High-resolution whole genome SNP array confirmed a low-level mosaicism (20%) in uncultured cells, underlining the value of array technology for identification studies. Subsequently, targeted Fluorescence In-Situ Hybridization in postmortem collected tissues demonstrated a similar low-level mosaicism, independently of the affected status of the tissue. Thus, a higher incidence of the genetic aberration in affected organs as lung and diaphragm cannot explain the severe phenotype of this complex CDH patient. Comparison with other described chromosome 5p and 12p anomalies indicated that half of the features presented in our patient (including the diaphragm defect) could be attributed to both chromosomal areas. In contrast, a few features such as the palpebral downslant, the broad nasal bridge, the micrognathia, microcephaly, abnormal dermatoglyphics and IUGR better fitted the 5p associated syndromes only. This study underlines the fact that low-level mosaicism can be associated with severe birth defects including CDH. The contribution of mosaicism to human diseases and specifically to congenital anomalies and spontaneous abortions becomes more and more accepted, although its phenotypic consequences are poorly described phenomena leading to counseling issues. Therefore, thorough follow-up of mosaic aberrations such as presented here is indicated in order to provide genetic counselors a more evidence based prediction of fetal prognosis in the future.

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.

Assessing the role of placental trisomy in preeclampsia and intrauterine growth restriction

OBJECTIVE

Prenatally diagnosed confined placental trisomy is associated with increased risk for intrauterine growth restriction (IUGR) and preeclampsia. However, it is unclear how often this might underlie pregnancy complications. Our objective was to evaluate the frequency and distribution of trisomic cells in placentae ascertained for IUGR and/or preeclampsia.

METHOD

Comparative genomic hybridization was applied to two uncultured biopsies from each of 61 placentae referred with maternal preeclampsia and/or IUGR, 11 cases with elevated maternal serum hCG and/or AFP but no IUGR or preeclampsia, and 85 control placentae.

RESULTS

Trisomy was observed in four placentae among the IUGR group (N = 43) but in no case of preeclampsia in the absence of IUGR (N = 18). Trisomy was observed in 1 of the 11 cases ascertained for abnormal maternal serum screen. Each of these five cases was mosaic and not all sampled sites showed the presence of trisomy. None of the 84 control placentas showed mosaic trisomy, although 1 case of nonmosaic 47,XXX was identified in this group.

CONCLUSION

In cases in which diagnosis of the cause of IUGR may provide some benefit, testing should be performed using uncultured cells from multiple placental biopsies for the accurate diagnosis of trisomy mosaicism.

Chromosomal mosaicism in mouse two-cell embryos after paternal exposure to acrylamide

Chromosomal mosaicism in human preimplantation embryos is a common cause of spontaneous abortions, however, our knowledge of its etiology is limited. We used multicolor fluorescence in situ hybridization painting to investigate whether paternally transmitted chromosomal aberrations result in mosaicism in mouse two-cell embryos. Paternal exposure to acrylamide, an important industrial chemical also found in tobacco smoke and generated during the cooking process of starchy foods, produced significant increases in chromosomally defective two-cell embryos, however, the effects were transient primarily affecting the postmeiotic stages of spermatogenesis. Comparisons with our previous study of zygotes demonstrated similar frequencies of chromosomally abnormal zygotes and two-cell embryos suggesting that there was no apparent selection against numerical or structural chromosomal aberrations. However, the majority of affected two-cell embryos were mosaics showing different chromosomal abnormalities in the two blastomeric metaphases. Analyses of chromosomal aberrations in zygotes and two-cell embryos showed a tendency for loss of acentric fragments during the first mitotic division of embryogenesis, whereas both dicentrics and translocations apparently underwent proper segregation. These results suggest that embryonic development can proceed up to the end of the second cell cycle of development in the presence of abnormal paternal chromosomes and that even dicentrics can persist through cell division. The high incidence of chromosomally mosaic two-cell embryos suggests that the first mitotic division of embryogenesis is prone to missegregation errors and that paternally transmitted chromosomal abnormalities increase the risk of missegregation leading to embryonic mosaicism.

Mosaic tetrasomy 12p with triplication of 12p detected by array-based comparative genomic hybridization of peripheral blood DNA

A patient whose dysmorphism at birth was not diagnostic for Pallister-Killian syndrome (PKS) was found to have mosaic tetrasomy 12p by an array-based comparative genomic hybridization of peripheral blood DNA. He was determined to be mosaic for 46,XY,trp(12)(p11.2 --> p13) in cultured skin fibroblasts. His appearance was typical for PKS at 4 months of age.

Molecular cytogenetic studies towards the full karyotype analysis of human blastocysts and cytotrophoblasts

Numerical chromosome aberrations in gametes typically lead to failed fertilization, spontaneous abortion or a chromosomally abnormal fetus. By means of preimplantation genetic diagnosis (PGD), we now can screen human embryos in vitro for aneuploidy before transferring the embryos to the uterus. PGD allows us to select unaffected embryos for transfer and increases the implantation rate in in vitro fertilization programs. Molecular cytogenetic analyses using multi-color fluorescence in situ hybridization (FISH) of blastomeres have become the major tool for preimplantation genetic screening of aneuploidy. However, current FISH technology can test for only a small number of chromosome abnormalities and hitherto failed to increase the pregnancy rates as expected. We are in the process of developing multi-color FISH-based technologies to score all 24 chromosomes in single cells within a three-day time limit, which we believe is vital to the clinical setting. Also, human placental cytotrophoblasts (CTBs) at the fetal-maternal interface acquire aneuploidies as they differentiate to an invasive phenotype. About 20-50% of invasive CTB cells from uncomplicated pregnancies were found to be aneuploid, suggesting that the acquisition of aneuploidy is an important component of normal placentation, perhaps limiting the proliferative and invasive potential of CTBs. Since most invasive CTBs are interphase cells and possess extreme heterogeneity, we applied multi-color FISH and repeated hybridizations to investigate the feasibility of a full karyotype analysis of individual CTBs. In summary, this study demonstrates the strength of Spectral Imaging analysis and repeated hybridizations, which provides a basis for full karyotype analysis of single interphase cells.

Diploid-aneuploid mosaicism in human embryos cultured to the blastocyst stage

OBJECTIVE

To examine diploid-aneuploid mosaicism in human in vitro cultured blastocysts.

DESIGN

A laboratory study on spare blastocysts from an IVF program.

SETTING

University hospital laboratory.

PATIENTS(S)

Forty-three couples undergoing IVF or intracytoplasmic sperm injection.

INTERVENTION(S)

Ninety-one blastocysts were spread for fluorescence in situ hybridization using the HCl-Tween 20 method. A total of 6,664 nuclei were analyzed for aneuploidy using fluorescent DNA probes specific to chromosomes 2, 7, and 18.

MAIN OUTCOME MEASURE(S)

The proportion of aneuploid cells within each blastocyst.

RESULTS(S)

The incidence of diploid-aneuploid mosaicism among 91 blastocysts examined was 17.6%. All of the mosaic blastocysts were abnormal for only one of the three chromosomes tested, with the incidence of involvement of chromosomes 2, 7, and 18 being 3.3%, 8.8%, and 5.5%, respectively. The majority of the mosaic blastocysts had low proportions of aneuploid cells. Ten of the 16 (62.5%) affected blastocysts were of morphology compatible with implantation.

CONCLUSION(S)

A considerable proportion of human IVF blastocysts show a form of mosaicism that has been observed in fetal and placental tissues. This mosaicism often arises at the final stage of preimplantation development in vitro and is present in blastocysts of morphology compatible with implantation.

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.

Aneuploidy screening in coelomic samples using fluorescencein situ hybridisation (FISH)

OBJECTIVES

Coelocentesis is the earliest invasive prenatal diagnostic procedure that has recently been used in ongoing pregnancies to identify single gene defects. Aneuploidy screening has not yet been performed in ongoing pregnancies following coelocentesis, but experimental studies have demonstrated the ability of determining the copy number of chromosomes 13, 18, 21, X and Y in uncultured coelomic samples, by FISH or PCR. The aim of this study was to extend previous studies and investigate the feasibility of analysing uncultured coelomic fluid samples for 11 chromosomes using fluorescence in situ hybridisation (FISH).

METHODS

Coelocentesis was performed in 12 singleton pregnancies at 6 to 9 weeks of gestation immediately before surgical termination of pregnancy. Fluorescence probes for chromosomes 3,7,9,13,16,17,18,21,22, X and Y were applied on uncultured coelomic-fluid samples and placental tissue. In cases where coelomic cells were not of a sufficient amount, chromosomes X and Y were analysed in a second layer of hybridisation.

RESULTS

Successful analysis by FISH was possible in all cases and the results from the coelomic fluid were concordant with those from the analysis of placental tissue and obtained within a few hours of receiving the samples. Problems associated with limited cell numbers were overcome by the application of a second layer of FISH. This sequential approach has also enabled accurate identification of maternal-cell contamination in male samples.

CONCLUSION

Analysis of 11 chromosomes using FISH in coelomic fluid samples is feasible and it has the potential to be applied for rapid aneuploidy screening, should coelocentesis be used clinically as an early, invasive prenatal diagnostic tool.

Fetal and placental chromosomal mosaicism revealed by QF-PCR in severe IUGR pregnancies

A number of genetic and environmental factors are taken into account as responsible for intrauterine growth restriction (IUGR); nevertheless, the relevance of genetic alteration in IUGR aetiology remains to be determined. The aim of this study was to investigate using a combined cytogenetic-molecular approach, improved by a new application of QF-PCR method, the presence of mosaic chromosomal changes in fetal/placental samples from 12 pregnancies with unexplained severe IUGR. This multiple approach allowed us to reveal and quantify subtle chromosomal mosaicisms with less than 5% of trisomic cells even in cases in which cytogenetic and FISH analyses failed to reveal them. These are three pregnancies with a mosaic trisomy for chromosomes 7, 2 and 14; the former case presented matUPD7 and was previously described in this journal (Placenta 22 (2001) 813) in association with pre- and postnatal growth restriction. It is intriguing that chromosomes 7, 2 and 14 are known or suspected to harbour imprinted genes, so that an unbalanced gene dosage in a subset of cells during embryonic development could lead to an early impairment of placental function. Our findings indicate that extensive molecular and cytogenetic studies of IUGR fetal and placental tissues are necessary to reveal at least part of the heterogeneous genetic lesions implicated in IUGR phenotypes.

Advances in molecular cytogenetics for the evaluation of mental retardation

Recent years have witnessed rapid advances in molecular cytogenetics and its impact in studying mental retardation (MR). We review new molecular cytogenetic methods, including interphase fluorescence in situ hyrbridization (FISH), comparative genomic hybridization (CGH), multicolor karyotyping, telomere FISH, primed in situ labeling (PRINS), genotyping, microdissection, and microarray for the evaluation of MR. These new methods are very useful in two major aspects: further characterization of chromosome abnormalities as detected with routine banding analysis, including additions, duplications, deletions, translocations, markers, or complex aberrations; and screening for "hidden" chromosome aberrations in patients with an apparently normal karyotype. These new methods have great diagnostic potential in prenatal, postnatal, and preimplantational settings. Although powerful, at this point, they are primarily research tools in nature. It is essential that these new methods be used in conjunction with standard methods in order to maximize obtainable information for better management of patients with MR.

Origin of amnion and implications for evaluation of the fetal genotype in cases of mosaicism

OBJECTIVE

To investigate presence of trisomy in amniotic epithelium (uncultured amnion) and mesenchyme (cultured amnion) from mosaic cases to understand the origins of these tissues and their relationship to pregnancy outcome.

METHODS

Polymerase chain reaction (PCR) of microsatellite loci was used to determine the presence of trisomy (of meiotic origin only) in amnion samples from 33 placentas previously ascertained because of a prenatal diagnosis of trisomy mosaicism that was predominantly confined to the placental tissues.

RESULTS

In 16 (48%) of 33 cases, trisomy was confirmed to be present by molecular analysis of uncultured amnion. In contrast, cytogenetic analysis of cultured amnion showed trisomy in only 2 of 20 informative cases. The molecular detection of trisomy in amnion was strongly associated with poor pregnancy outcome (intrauterine growth restriction, fetal anomalies and/or intrauterine/neonatal death) even when analysis was limited to cases negative for the trisomy on amniotic fluid (N = 22, p = 0.0005).

CONCLUSIONS

We infer that amniotic mesenchyme (usually diploid) derives from early embryonic mesoderm of the primitive streak and not from the hypoblast as is commonly cited. Trisomy in amniotic epithelium suggests that high numbers of abnormal cells were present in the epiblast, and this correlates with poor outcome even when the subsequently derived fetus and amniotic mesenchyme appear to carry only diploid cells.

CGH in the detection of confined placental mosaicism (CPM) in placentas of abnormal pregnancies

Comparative genomic hybridization (CGH) was applied to samples taken from various sites of placentas originating from complicated pregnancies: 24 with intrauterine growth restriction (IUGR), one with multiple fetal malformation, one with toxemia, one with hydrocephalus and two with undetectable maternal serum alpha-fetoprotein (MSAFP). One of the most common aberrations in the IUGR cases was the addition of a whole or part of the X chromosome. Other aberrations such as additional Y chromosome or of 13(q22) or loss of chromosome 17 also appeared in different cases. In one IUGR case trisomy 8 (in one site) and 47,XXY (in all sites) were detected. In the two cases with undetectable MSAFP monosomy 16 was found. Some of the results were also confirmed by the FISH technique. In all the control cases (six normal and five with aneuploidy) CGH concurred with the known karyotype. Our results demonstrate the usefulness of the CGH technique in the genetic evaluation of fresh and paraffin embedded placentas in problematic pregnancies even when morphology is normal. However, it is very important to take multiple samples from different sites of the placenta.

High resolution comparative genomic hybridisation in clinical cytogenetics

High resolution comparative genomic hybridisation (HR-CGH) is a diagnostic tool in our clinical cytogenetics laboratory. The present survey reports the results of 253 clinical cases in which 47 abnormalities were detected. Among 144 dysmorphic and mentally retarded subjects with a normal conventional karyotype, 15 (10%) had small deletions or duplications, of which 11 were interstitial. In addition, a case of mosaic trisomy 9 was detected. Among 25 dysmorphic and mentally retarded subjects carrying apparently balanced de novo translocations, four had deletions at translocation breakpoints and two had deletions elsewhere in the genome. Seventeen of 19 complex rearrangements were clarified by HR-CGH. A small supernumerary marker chromosome occurring with low frequency and the breakpoint of a mosaic r(18) case could not be clarified. Three of 19 other abnormalities could not be confirmed by HR-CGH. One was a Williams syndrome deletion and two were DiGeorge syndrome deletions, which were apparently below the resolution of HR-CGH. However, we were able to confirm Angelman and Prader-Willi syndrome deletions, which are about 3-5 Mb. We conclude that HR-CGH should be used for the evaluation of (1) dysmorphic and mentally retarded subjects where normal karyotyping has failed to show abnormalities, (2) dysmorphic and mentally retarded subjects carrying apparently balanced de novo translocations, (3) apparently balanced de novo translocations detected prenatally, and (4) for clarification of complex structural rearrangements.

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.

Identification of two de novo partial trisomies by comparative genomic hybridization

We report the use of comparative genomic hybridization (CGH) to define the extra chromosome region present in two de novo partial trisomies 15q25-qter and Xp21-pter, which could not be clarified by conventional G-banding. Investigation with fluorescence in situ hybridization (FISH) revealed that the partial trisomy corresponded to an unbalanced translocation between Y and 15 chromosomes in 1 patient and an unbalanced X/X reorganization in the other patient. The combination of classical karyotyping, CGH, and FISH is useful for the identification and characterization of partial trisomies in clinical diagnostic laboratories, in order to delineate the chromosome regions implicated in specific clinical disorders.

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.