Talk:Prenatal Diagnosis

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On this website the Discussion Tab or "talk pages" for a topic has been used for several purposes: References - recent and historic that relates to the topic Additional topic information - currently prepared in draft format Links - to related webpages Topic page - an edit history as used on other Wiki sites Lecture/Practical - student feedback Student Projects - online project discussions. Links: Pubmed Most Recent | Reference Tutorial | Journal Searches Glossary Links Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link Cite this page: Hill, M.A. (2024, June 3) Embryology Prenatal Diagnosis. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Prenatal_Diagnosis

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Cordocentesis

<pubmed limit=5>Cordocentesis</pubmed>

2017

Prenatal Diagnosis: Screening and Diagnostic Tools

Obstet Gynecol Clin North Am. 2017 Jun;44(2):245-256. doi: 10.1016/j.ogc.2017.02.004.

Carlson LM1, Vora NL2.

Abstract

The American Congress of Obstetricians and Gynecologists recommends that all pregnant women be offered aneuploidy screening or diagnostic testing. A myriad of screening and testing options are available to patients based on their risk profile and gestational age. Screening options include traditional serum analyte screening, such as first-trimester screening or quadruple screening, and more recently, cell-free DNA. Diagnostic testing choices include chorionic villus sampling and amniocentesis. The number of screening and diagnostic modalities complicates prenatal counseling for physicians and can be difficult for patients to grasp. Appropriate pretest and posttest counseling is important to ensure adequate understanding of results and ensure testing strategy is concordant with patient goals. Copyright © 2017 Elsevier Inc. All rights reserved.

KEYWORDS: Amniocentesis; Aneuploidy; Cell-free DNA; Chorionic villus sampling; Genetic screening; Noninvasive prenatal screening PMID 28499534 DOI: 10.1016/j.ogc.2017.02.004

2016

Fetal genome profiling at 5 weeks of gestation after noninvasive isolation of trophoblast cells from the endocervical canal

Sci Transl Med. 2016 Nov 2;8(363):363re4.

Jain CV1,2, Kadam L1,2, van Dijk M3, Kohan-Ghadr HR1, Kilburn BA1, Hartman C4, Mazzorana V4, Visser A3, Hertz M1, Bolnick AD1, Fritz R1, Armant DR1,5,6, Drewlo S7.

Abstract

Single-gene mutations account for more than 6000 diseases, 10% of all pediatric hospital admissions, and 20% of infant deaths. Down syndrome and other aneuploidies occur in more than 0.2% of births worldwide and are on the rise because of advanced reproductive age. Birth defects of genetic origin can be diagnosed in utero after invasive extraction of fetal tissues. Noninvasive testing with circulating cell-free fetal DNA is limited by a low fetal DNA fraction. Both modalities are unavailable until the end of the first trimester. We have isolated intact trophoblast cells from Papanicolaou smears collected noninvasively at 5 to 19 weeks of gestation for next-generation sequencing of fetal DNA. Consecutive matched maternal, placental, and fetal samples (n = 20) were profiled by multiplex targeted DNA sequencing of 59 short tandem repeat and 94 single-nucleotide variant sites across all 24 chromosomes. The data revealed fetal DNA fractions of 85 to 99.9%, with 100% correct fetal haplotyping. This noninvasive platform has the potential to provide comprehensive fetal genomic profiling as early as 5 weeks of gestation.

Copyright © 2016, American Association for the Advancement of Science.

PMID 27807286

DOI: 10.1126/scitranslmed.aah4661

Open source non-invasive prenatal testing platform and its performance in a public health laboratory

Prenat Diagn. 2016 Mar 30. doi: 10.1002/pd.4819. [Epub ahead of print]

Johansen P1, Richter SR1, Balslev-Harder M1, Miltoft CB2, Tabor A2, Duno M3, Kjaergaard S1.

Abstract

OBJECTIVE: To introduce NIPT for fetal autosomal trisomies and gender in a Danish public health setting, using semi-conductor sequencing and published open source scripts for analysis. METHODS: Plasma derived DNA from a total of 375 pregnant women (divided into 3 datasets) was whole-genome sequenced on the Ion Proton™ platform and analyzed using a pipeline based on WISECONDOR for fetal autosomal aneuploidy detection and SeqFF for fetal DNA fraction estimation. We furthermore validated a fetal sex determination analysis. RESULTS: The pipeline correctly detected 27/27 trisomy 21, 4/4 trisomy 18 and 3/3 trisomy 13 fetuses. Neither false negatives nor false positives (chromosomes 13, 18 and 21) were observed in our validation dataset. Fetal sex was identified correctly in all but one triploid fetus (172/173). SeqFF showed a strong correlation (R2  = 0.72) to Y-chromosomal content of the male fetus samples. DISCUSSION: We have implemented NIPT into Danish health care using published open source scripts for autosomal aneuploidy detection and fetal DNA fraction estimation showing excellent false negative and false positive rates. SeqFF provides a good estimation of fetal DNA fraction. This coupled with an analysis of fetal sex provides a complete NIPT workflow, which may easily be adapted for implementation in other public health laboratories. This article is protected by copyright. All rights reserved.

PMID 27027563

2015

An Economic Analysis of Cell-Free DNA Non-Invasive Prenatal Testing in the US General Pregnancy Population

PLoS One. 2015 Jul 9;10(7):e0132313. doi: 10.1371/journal.pone.0132313. eCollection 2015. Benn P1, Curnow KJ2, Chapman S3, Michalopoulos SN4, Hornberger J5, Rabinowitz M3.

Abstract

OBJECTIVE: Analyze the economic value of replacing conventional fetal aneuploidy screening approaches with non-invasive prenatal testing (NIPT) in the general pregnancy population. METHODS: Using decision-analysis modeling, we compared conventional screening to NIPT with cell-free DNA (cfDNA) analysis in the annual US pregnancy population. Sensitivity and specificity for fetal aneuploidies, trisomy 21, trisomy 18, trisomy 13, and monosomy X, were estimated using published data and modeling of both first- and second trimester screening. Costs were assigned for each prenatal test component and for an affected birth. The overall cost to the healthcare system considered screening costs, the number of aneuploid cases detected, invasive procedures performed, procedure-related euploid losses, and affected pregnancies averted. Sensitivity analyses evaluated the effect of variation in parameters. Costs were reported in 2014 US Dollars. RESULTS: Replacing conventional screening with NIPT would reduce healthcare costs if it can be provided for $744 or less in the general pregnancy population. The most influential variables were timing of screening entry, screening costs, and pregnancy termination rates. Of the 13,176 affected pregnancies undergoing screening, NIPT detected 96.5% (12,717/13,176) of cases, compared with 85.9% (11,314/13,176) by conventional approaches. NIPT reduced invasive procedures by 60.0%, with NIPT and conventional methods resulting in 24,596 and 61,430 invasive procedures, respectively. The number of procedure-related euploid fetal losses was reduced by 73.5% (194/264) in the general screening population. CONCLUSION: Based on our analysis, universal application of NIPT would increase fetal aneuploidy detection rates and can be economically justified. Offering this testing to all pregnant women is associated with substantial prenatal healthcare benefits.

PMID 26158465

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0132313

2014

Fetal MRI: An approach to practice: A review

J Adv Res. 2014 Sep;5(5):507-23. doi: 10.1016/j.jare.2013.06.001. Epub 2013 Jun 11.

Saleem SN1.

Abstract

MRI has been increasingly used for detailed visualization of the fetus in utero as well as pregnancy structures. Yet, the familiarity of radiologists and clinicians with fetal MRI is still limited. This article provides a practical approach to fetal MR imaging. Fetal MRI is an interactive scanning of the moving fetus owed to the use of fast sequences. Single-shot fast spin-echo (SSFSE) T2-weighted imaging is a standard sequence. T1-weighted sequences are primarily used to demonstrate fat, calcification and hemorrhage. Balanced steady-state free-precession (SSFP), are beneficial in demonstrating fetal structures as the heart and vessels. Diffusion weighted imaging (DWI), MR spectroscopy (MRS), and diffusion tensor imaging (DTI) have potential applications in fetal imaging. Knowing the developing fetal MR anatomy is essential to detect abnormalities. MR evaluation of the developing fetal brain should include recognition of the multilayered-appearance of the cerebral parenchyma, knowledge of the timing of sulci appearance, myelination and changes in ventricular size. With advanced gestation, fetal organs as lungs and kidneys show significant changes in volume and T2-signal. Through a systematic approach, the normal anatomy of the developing fetus is shown to contrast with a wide spectrum of fetal disorders. The abnormalities displayed are graded in severity from simple common lesions to more complex rare cases. Complete fetal MRI is fulfilled by careful evaluation of the placenta, umbilical cord and amniotic cavity. Accurate interpretation of fetal MRI can provide valuable information that helps prenatal counseling, facilitate management decisions, guide therapy, and support research studies. KEYWORDS: Anomalies; Fetal; MRI; Prenatal

PMID 25685519

http://www.sciencedirect.com/science/article/pii/S2090123213000805

2013

Noninvasive Prenatal Testing: The Future Is Now

Rev Obstet Gynecol. 2013;6(2):48-62.

Norwitz ER1, Levy B2.

Abstract

Prenatal detection of chromosome abnormalities has been offered for more than 40 years, first by amniocentesis in the early 1970s and additionally by chorionic villus sampling (CVS) in the early 1980s. Given the well-recognized association between increasing maternal age and trisomy,1-3 the primary utilization of prenatal testing has been by older mothers. This has drastically reduced the incidence of aneuploid children born to older mothers.4 Although younger women have relatively low risks of conceiving a child with aneuploidy, the majority of pregnant women are in their late teens, 20s, and early 30s. As such, most viable aneuploid babies are born to these younger mothers.5 Invasive prenatal diagnosis (CVS and amniocentesis) is not a feasible option for all low-risk mothers, as these procedures carry a small but finite risk and would ultimately cause more miscarriages than they would detect aneuploidy. For this reason, a number of noninvasive tests have been developed-including first-trimester risk assessment at 11 to 14 weeks, maternal serum analyte (quad) screening at 15 to 20 weeks, and sonographic fetal structural survey at 18 to 22 weeks-all of which are designed to give a woman an adjusted (more accurate) estimate of having an aneuploid fetus using as baseline her a priori age-related risk. Ultrasound and maternal serum analysis are considered screening procedures and both require follow up by CVS or amniocentesis in screen-positive cases for a definitive diagnosis of a chromosome abnormality in the fetus. The ability to isolate fetal cells and fetal DNA from maternal blood during pregnancy has opened up exciting opportunities for improved noninvasive prenatal testing (NIPT). Direct analysis of fetal cells from maternal circulation has been challenging given the scarcity of fetal cells in maternal blood (1:10,000-1:1,000,000) and the focus has shifted to the analysis of cell-free fetal DNA, which is found at a concentration almost 25 times higher than that available from nucleated blood cells extracted from a similar volume of whole maternal blood. There have now been numerous reports on the use of cell-free DNA (cfDNA) for NIPT for chromosomal aneuploidies-especially trisomy (an extra copy of a chromosome) or monosomy (a missing chromosome)-and a number of commercial products are already being marketed for this indication. This article reviews the various techniques being used to analyze cell-free DNA in the maternal circulation for the prenatal detection of chromosome abnormalities and the evidence in support of each. A number of areas of ongoing controversy are addressed, including the timing of maternal blood sampling, the need for genetic counseling, and the use of confirmatory invasive testing. Future applications for this technology are also reviewed. KEYWORDS: Cell-free fetal DNA, Noninvasive prenatal testing, Prenatal diagnosis, Trisomy 21

PMID 24466384

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0132313

Noninvasive whole-genome sequencing of a human fetus

Sci Transl Med. 2012 Jun 6;4(137):137ra76. doi: 10.1126/scitranslmed.3004323.

Kitzman JO, Snyder MW, Ventura M, Lewis AP, Qiu R, Simmons LE, Gammill HS, Rubens CE, Santillan DA, Murray JC, Tabor HK, Bamshad MJ, Eichler EE, Shendure J. Source Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA.

Abstract

Analysis of cell-free fetal DNA in maternal plasma holds promise for the development of noninvasive prenatal genetic diagnostics. Previous studies have been restricted to detection of fetal trisomies, to specific paternally inherited mutations, or to genotyping common polymorphisms using material obtained invasively, for example, through chorionic villus sampling. Here, we combine genome sequencing of two parents, genome-wide maternal haplotyping, and deep sequencing of maternal plasma DNA to noninvasively determine the genome sequence of a human fetus at 18.5 weeks of gestation. Inheritance was predicted at 2.8 × 10(6) parental heterozygous sites with 98.1% accuracy. Furthermore, 39 of 44 de novo point mutations in the fetal genome were detected, albeit with limited specificity. Subsampling these data and analyzing a second family trio by the same approach indicate that parental haplotype blocks of ~300 kilo-base pairs combined with shallow sequencing of maternal plasma DNA is sufficient to substantially determine the inherited complement of a fetal genome. However, ultradeep sequencing of maternal plasma DNA is necessary for the practical detection of fetal de novo mutations genome-wide. Although technical and analytical challenges remain, we anticipate that noninvasive analysis of inherited variation and de novo mutations in fetal genomes will facilitate prenatal diagnosis of both recessive and dominant Mendelian disorders.

PMID 22674554

2012

A noninvasive test to determine paternity in pregnancy

N Engl J Med. 2012 May 3;366(18):1743-5. Guo X, Bayliss P, Damewood M, Varney J, Ma E, Vallecillo B, Dhallan R.

Our approach shows that noninvasive prenatal paternity testing can be performed within the first trimester with the use of a maternal blood sample.

PMID 22551147

The ESHRE PGD Consortium: 10 years of data collection

Hum Reprod Update. 2012 May-Jun;18(3):234-47. Epub 2012 Feb 16.

Harper JC, Wilton L, Traeger-Synodinos J, Goossens V, Moutou C, SenGupta SB, Pehlivan Budak T, Renwick P, De Rycke M, Geraedts JP, Harton G. Source UCL Centre for PG&D, Institute for Women' s Health, University College London, London, UK. joyce.harper@ucl.ac.uk

Abstract BACKGROUND: Since it was established in 1997, the ESHRE PGD Consortium has been collecting data from international preimplantation genetic diagnosis (PGD) centres. Ten papers have been published, including data from January 1997 to December 2007. METHODS: The data collection originally used a hard-copy format, then an excel database and finally a FileMaker Pro database. The indications are divided into five categories: PGD for chromosome abnormalities, sexing for X-linked disease, PGD for single gene defects, preimplantation genetic screening (PGS) and PGD for social sexing. The main end-points are pregnancy outcome and follow-up of deliveries. RESULTS: In data collection I, 16 centres contributed data, which increased to 57 centres by data X (average of 39 centres per data collection). These centres contributed data on over 27 000 cycles that reached oocyte retrieval. Of these cycles, 61% were for aneuploidy screening, 17% for single gene disorders, 16% for chromosomal abnormalities, 4% for sexing of X-linked disease and 2% for social sexing. Cumulatively, 5187 clinical pregnancies gave rise to 4140 deliveries and 5135 newborns (singletons: 3182, twins: 921, triplets: 37). CONCLUSIONS: In this paper, we present an overview of the first 10 years of PGD data, highlighting trends. These include the introduction of laser-assisted biopsy, an increase in polar body and trophectoderm biopsy, new strategies, methodologies and technologies for diagnosis, including recently arrays, and the more frequent use of freezing biopsied embryos. The Consortium data reports represent a valuable resource for information about the practice of PGD.

PMID 22343781

Hum Genet. 2012 Feb;131(2):175-86. doi: 10.1007/s00439-011-1056-z. Epub 2011 Jul 12. Preimplantation genetic diagnosis: state of the art 2011. Harper JC, Sengupta SB. Source UCL Centre for PG&D, Institute for Womens Health, University College London, London, UK. joyce.harper@ucl.ac.uk Abstract For the last 20 years, preimplantation genetic diagnosis (PGD) has been mostly performed on cleavage stage embryos after the biopsy of 1-2 cells and PCR and FISH have been used for the diagnosis. The main indications have been single gene disorders and inherited chromosome abnormalities. Preimplantation genetic screening (PGS) for aneuploidy is a technique that has used PGD technology to examine chromosomes in embryos from couples undergoing IVF with the aim of helping select the chromosomally 'best' embryo for transfer. It has been applied to patients of advanced maternal age, repeated implantation failure, repeated miscarriages and severe male factor infertility. Recent randomised controlled trials (RCTs) have shown that PGS performed on cleavage stage embryos for a variety of indications does not improve delivery rates. At the cleavage stage, the cells biopsied from the embryo are often not representative of the rest of the embryo due to chromosomal mosaicism. There has therefore been a move towards blastocyst and polar body biopsy, depending on the indication and regulations in specific countries (in some countries, biopsy of embryos is not allowed). Blastocyst biopsy has an added advantage as vitrification of blastocysts, even post biopsy, has been shown to be a very successful method of cryopreserving embryos. However, mosaicism is also observed in blastocysts. There have been dramatic changes in the method of diagnosing small numbers of cells for PGD. Both array-comparative genomic hybridisation and single nucleotide polymorphism arrays have been introduced clinically for PGD and PGS. For PGD, the use of SNP arrays brings with it ethical concerns as a large amount of genetic information will be available from each embryo. For PGS, RCTs need to be conducted using both array-CGH and SNP arrays to determine if either will result in an increase in delivery rates.

PMID 21748341

2011

Antenatal screening - the first and second trimester

Aust Fam Physician. 2011 Oct;40(10):785-7.

Bonacquisto L. Source Maternal Serum Screening Laboratory, VCGS Pathology, Murdoch Childrens Research Institute, Royal Childrens Hospital, Parkville, Victoria. leonard.bonacquisto@ghsv.org.au

Abstract

Antenatal screening is performed in the first or second trimester to determine whether a pregnant woman's baby has an increased risk of having Down syndrome (a chromosomal abnormality affecting one in 500 pregnancies), Edward syndrome (one in 3000) or open neural tube defects (one in 750). First trimester screening combines results from a blood test with a nuchal translucency and nasal bone obstetric scan during the first trimester of pregnancy. Second trimester screening requires only a blood test. The screening approach varies across Australia; this article primarily describes the Victorian protocol.

PMID 22003480

http://www.racgp.org.au/afp/201110/44361

An update of preimplantation genetic diagnosis in gene diseases, chromosomal translocation, and aneuploidy screening

Clin Exp Reprod Med. 2011 Sep;38(3):126-34. Epub 2011 Sep 30.

Chang LJ, Chen SU, Tsai YY, Hung CC, Fang MY, Su YN, Yang YS. Source Department of Obstetrics and Gynecology, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan. Abstract Preimplantation genetic diagnosis (PGD) is gradually widely used in prevention of gene diseases and chromosomal abnormalities. Much improvement has been achieved in biopsy technique and molecular diagnosis. Blastocyst biopsy can increase diagnostic accuracy and reduce allele dropout. It is cost-effective and currently plays an important role. Whole genome amplification permits subsequent individual detection of multiple gene loci and screening all 23 pairs of chromosomes. For PGD of chromosomal translocation, fluorescence in-situ hybridization (FISH) is traditionally used, but with technical difficulty. Array comparative genomic hybridization (CGH) can detect translocation and 23 pairs of chromosomes that may replace FISH. Single nucleotide polymorphisms array with haplotyping can further distinguish between normal chromosomes and balanced translocation. PGD may shorten time to conceive and reduce miscarriage for patients with chromosomal translocation. PGD has a potential value for mitochondrial diseases. Preimplantation genetic haplotyping has been applied for unknown mutation sites of single gene disease. Preimplantation genetic screening (PGS) using limited FISH probes in the cleavage-stage embryo did not increase live birth rates for patients with advanced maternal age, unexplained recurrent abortions, and repeated implantation failure. Polar body and blastocyst biopsy may circumvent the problem of mosaicism. PGS using blastocyst biopsy and array CGH is encouraging and merit further studies. Cryopreservation of biopsied blastocysts instead of fresh transfer permits sufficient time for transportation and genetic analysis. Cryopreservation of embryos may avoid ovarian hyperstimulation syndrome and possible suboptimal endometrium.

PMID 22384431

Non-invasive tool for foetal sex determination in early gestational age

Haemophilia. 2011 Apr 15. doi: 10.1111/j.1365-2516.2011.02537.x. [Epub ahead of print]

Mortarino M, Garagiola I, Lotta LA, Siboni SM, Semprini AE, Peyvandi F. Source U.O.S. Dipartimentale per la Diagnosi e la Terapia delle Coagulopatie, Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, University of Milan and Luigi Villa Foundation, Milan, Italy Clinica Ostetrica e Ginecologica, Ospedale Luigi Sacco, University of Milan, Milan, Italy. Abstract

Summary.  Free foetal DNA in maternal blood during early pregnancy is an ideal source of foetal genetic material for non-invasive prenatal diagnosis. The aim of this study was to evaluate the use of free foetal DNA analysis at early gestational age as pretest for the detection of specific Y-chromosome sequences in maternal plasma of women who are carriers of X-linked disorders, such as haemophilia. Real-time quantitative PCR analysis of maternal plasma was performed for the detection of the SRY or DYS14 sequence. A group of 208 pregnant women, at different gestational periods from 4 to 12 weeks, were tested to identify the optimal period to obtain an adequate amount of foetal DNA for prenatal diagnosis. Foetal gender was determined in 181 pregnant women sampled throughout pregnancy. Pregnancy outcome and foetal gender were confirmed using karyotyping, ultrasonography or after birth. The sensitivity, which was low between 4th and 7th week (mean 73%), increased significantly after 7+1th weeks of gestation (mean 94%). The latter sensitivity after 7+1th week of gestation is associated to a high specificity (100%), with an overall accuracy of 96% for foetal gender determination. This analysis demonstrates that foetal gender determination in maternal plasma is reliable after the 9th week of gestation and it can be used, in association with ultrasonography, for screening to determine the need for chorionic villus sampling for prenatal diagnosis of X-linked disorders, such as haemophilia.

© 2011 Blackwell Publishing Ltd.

PMID 21492325

Hum Reprod. 2011 Nov;26(11):3173-80. Epub 2011 Sep 9. Polar body array CGH for prediction of the status of the corresponding oocyte. Part I: clinical results. Geraedts J, Montag M, Magli MC, Repping S, Handyside A, Staessen C, Harper J, Schmutzler A, Collins J, Goossens V, van der Ven H, Vesela K, Gianaroli L. Source Department of Genetics and Cell Biology, Research Institute GROW, Faculty of Health, Medicine and Life Sciences, Maastricht University, PO Box 5800, Maastricht, AZ 6202, The Netherlands. joep.geraedts@mumc.nl Abstract BACKGROUND: Several randomized controlled trials have not shown a benefit from preimplantation genetic screening (PGS) biopsy of cleavage-stage embryos and assessment of up to 10 chromosomes for aneuploidy. Therefore, a proof-of-principle study was planned to determine the reliability of alternative form of PGS, i.e. PGS by polar body (PB) biopsy, with whole genome amplification and microarray-based comparative genomic hybridization (array CGH) analysis. METHODS: In two centres, all mature metaphase II oocytes from patients who consented to the study were fertilized by ICSI. The first and second PBs (PB1and PB2) were biopsied and analysed separately for chromosome copy number by array CGH. If either or both of the PBs were found to be aneuploid, the corresponding zygote was then also processed by array CGH for concordance analysis. RESULTS: Both PBs were biopsied from a total of 226 zygotes from 42 cycles (average 5.5 per cycle; range 1-15) in 41 couples with an average maternal age of 40.0 years. Of these, the ploidy status of the zygote could be predicted in 195 (86%): 55 were euploid (28%) and 140 were aneuploid (72%). With only one exception, there was at least one predicted aneuploid zygote in each cycle and in 19 out of 42 cycles (45%), all zygotes were predicted to be aneuploid. Fresh embryos were transferred in the remaining 23 cycles (55%), and one frozen transfer was done. Eight patients had a clinical pregnancy of which seven were evolutive (ongoing pregnancy rates: 17% per cycle and 30% per transfer). The ploidy status of 156 zygotes was successfully analysed by array CGH: 38 (24%) were euploid and 118 (76%) were aneuploid. In 138 cases complete information was available on both PBs and the corresponding zygotes. In 130 (94%), the ploidy status of the zygote was concordant with the ploidy status of the PBs and in 8 (6%), the results were discordant. CONCLUSIONS: This proof-of-principle study indicates that the ploidy of the zygote can be predicted with acceptable accuracy by array CGH analysis of both PBs.

PMID 21908463

2010

FISH for pre-implantation genetic diagnosis

Scriven PN, Ogilvie CM. Methods Mol Biol. 2010;659:269-82.

Pre-implantation genetic diagnosis (PGD) is an established alternative to pre-natal diagnosis, and involves selecting pre-implantation embryos from a cohort generated by assisted reproduction technology (ART). This selection may be required because of familial monogenic disease (e.g. cystic fibrosis), or because one partner carries a chromosome rearrangement (e.g. a two-way reciprocal translocation). PGD is available for couples who have had previous affected children, and/or in the case of chromosome rearrangements, recurrent miscarriages, or infertility. Oocytes aspirated following ovarian stimulation are fertilized by in vitro immersion in semen (IVF) or by intracytoplasmic injection of individual spermatocytes (ICSI). Pre-implantation cleavage-stage embryos are biopsied, usually by the removal of a single cell on day 3 post-fertilization, and the biopsied cell is tested to establish the genetic status of the embryo.Fluorescence in situ hybridization (FISH) on the fixed nuclei of biopsied cells with target-specific DNA probes is the technique of choice to detect chromosome imbalance associated with chromosome rearrangements, and to select female embryos in families with X-linked disease for which there is no mutation-specific test. FISH has also been used to screen embryos for sporadic chromosome aneuploidy (also known as PGS or PGD-AS) in order to try and improve the efficiency of assisted reproduction; however, due to the unacceptably low predictive accuracy of this test using FISH, it is not recommended for routine clinical use.This chapter describes the selection of suitable probes for single-cell FISH, assessment of the analytical performance of the test, spreading techniques for blastomere nuclei, and in situ hybridization and signal scoring, applied to PGD in a clinical setting.

PMID 20809319