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Girardet A.,Montpellier University Hospital Center | Girardet A.,Montpellier University | Girardet A.,French Institute of Health and Medical Research | Viart V.,Montpellier University Hospital Center | And 25 more authors.
European Journal of Human Genetics | Year: 2016

Cystic fibrosis (CF) is one of the most common indications for preimplantation genetic diagnosis (PGD) for single gene disorders, giving couples the opportunity to conceive unaffected children without having to consider termination of pregnancy. However, there are no available standardized protocols, so that each center has to develop its own diagnostic strategies and procedures. Furthermore, reproductive decisions are complicated by the diversity of disease-causing variants in the CFTR (cystic fibrosis transmembrane conductance regulator) gene and the complexity of correlations between genotypes and associated phenotypes, so that attitudes and practices toward the risks for future offspring can vary greatly between countries. On behalf of the EuroGentest Network, eighteen experts in PGD and/or molecular diagnosis of CF from seven countries attended a workshop held in Montpellier, France, on 14 December 2011. Building on the best practice guidelines for amplification-based PGD established by ESHRE (European Society of Human Reproduction and Embryology), the goal of this meeting was to formulate specific guidelines for CF-PGD in order to contribute to a better harmonization of practices across Europe. Different topics were covered including variant nomenclature, inclusion criteria, genetic counseling, PGD strategy and reporting of results. The recommendations are summarized here, and updated information on the clinical significance of CFTR variants and associated phenotypes is presented. © 2016 Macmillan Publishers Limited.


Deans Z.,Royal Infirmary | Fiorentino F.,Genoma Laboratories | Biricik A.,Genoma Laboratories | Traeger-Synodinos J.,National and Kapodistrian University of Athens | And 6 more authors.
European Journal of Human Genetics | Year: 2013

Preimplantation genetic diagnosis (PGD) was first performed over 20 years ago and has become an accepted part of genetic testing and assisted reproduction worldwide. The techniques and protocols necessary to carry out genetic testing at the single-cell level can be difficult to master and have been developed independently by the laboratories worldwide offering preimplantation testing. These factors indicated the need for an external quality assessment (EQA) scheme for monogenic disease PGD. Toward this end, the European Society for Human Reproduction and Embryology came together with United Kingdom National External Quality Assessment Services for Molecular Genetics, to create a pilot EQA scheme followed by practical EQA schemes for all interested parties. Here, we detail the development of the pilot scheme as well as development and findings from the practical (clinical) schemes that have followed. Results were generally acceptable and there was marked improvement in results and laboratory scores for those labs that participated in multiple schemes. Data from the first three schemes indicate that the EQA scheme is working as planned and has helped laboratories improve their techniques and result reporting. The EQA scheme for monogenic PGD will continue to be developed to offer assessment for other monogenic disorders. © 2013 Macmillan Publishers Limited. All rights reserved.


Fassihi H.,King's College London | Liu L.,Robin Eady National Diagnostic Epidermolysis Bullosa Research Laboratory | Renwick P.J.,Center for Preimplantation Genetic Diagnosis | Braude P.R.,Center for Preimplantation Genetic Diagnosis | McGrath J.A.,King's College London
British Journal of Dermatology | Year: 2010

Background Herlitz junctional epidermolysis bullosa (HJEB) is a severe, life-threatening, autosomal recessive blistering skin disease for which no cure is currently available. Prenatal diagnosis for couples at risk is feasible through fetal skin biopsy or analysis of DNA extracted from chorionic villi, but these methods can be applied only after pregnancy has been established. An alternative approach, which involves the analysis of single cells from embryos prior to establishment of pregnancy, is preimplantation genetic diagnosis (PGD). Until now, its clinical uptake has been hindered by lengthy delays in establishing mutation-specific protocols, and by the small amount of template DNA that can be obtained from a single cell. A new method that addresses these problems, preimplantation genetic haplotyping (PGH), relies on whole genome amplification followed by haplotyping of multiple polymorphic markers using standard DNA-based polymerase chain reaction (PCR) assays. Objectives To design and validate a generic PGH assay for HJEB and to transfer this into clinical practice. Materials and methods We established a multiplex PCR-based PGH assay involving 16 markers within and flanking the LAMB3 gene (the most frequently mutated gene in HJEB). The assay was then validated in 10 families with at least one previously affected offspring. After licensing by the Human Fertilisation and Embryology Authority (HFEA), the new test was used for PGD in a couple at risk of HJEB. Results The chromosome 1 LAMB3 markers within the assay were shown to be of sufficient heterogeneity to have widespread application for preimplantation testing of HJEB. In one couple that were heterozygous carriers of nonsense mutations in LAMB3, we used the new assay to identify unaffected embryos in a series of PGD cycles. Pregnancy was established in the third PGD cycle and a healthy, unaffected child was born. DNA analysis of cord blood confirmed the predicted single-cell mutation status of wild-type LAMB3 alleles. Conclusions PGH represents a major step forward in widening the scope and availability of preimplantation testing for serious mapped single-gene disorders. We have established a generic test that is suitable for the majority of couples at risk of HJEB. © 2010 British Association of Dermatologists.


PubMed | Reprogenetics, Autonomous University of Barcelona, Center for Medical Genetics Brussel, Manchester Center for Genomic Medicine and 5 more.
Type: Journal Article | Journal: European journal of human genetics : EJHG | Year: 2016

Cystic fibrosis (CF) is one of the most common indications for preimplantation genetic diagnosis (PGD) for single gene disorders, giving couples the opportunity to conceive unaffected children without having to consider termination of pregnancy. However, there are no available standardized protocols, so that each center has to develop its own diagnostic strategies and procedures. Furthermore, reproductive decisions are complicated by the diversity of disease-causing variants in the CFTR (cystic fibrosis transmembrane conductance regulator) gene and the complexity of correlations between genotypes and associated phenotypes, so that attitudes and practices toward the risks for future offspring can vary greatly between countries. On behalf of the EuroGentest Network, eighteen experts in PGD and/or molecular diagnosis of CF from seven countries attended a workshop held in Montpellier, France, on 14 December 2011. Building on the best practice guidelines for amplification-based PGD established by ESHRE (European Society of Human Reproduction and Embryology), the goal of this meeting was to formulate specific guidelines for CF-PGD in order to contribute to a better harmonization of practices across Europe. Different topics were covered including variant nomenclature, inclusion criteria, genetic counseling, PGD strategy and reporting of results. The recommendations are summarized here, and updated information on the clinical significance of CFTR variants and associated phenotypes is presented.


Scriven P.N.,Guys Hospital | Scriven P.N.,Center for Preimplantation Genetic Diagnosis | Bossuyt P.M.M.,University of Amsterdam
Human Reproduction | Year: 2010

BACKGROUND: The aim of this study was to develop and use theoretical models to investigate the accuracy of the fluorescence in situ hybridization (FISH) technique in testing a single nucleus from a preimplantation embryo without the complicating effect of mosaicism. METHODS: Mathematical models were constructed for three different applications of FISH in preimplantation genetic testing (sex determination for sex-linked diseases, two-way reciprocal translocations and sporadic chromosome aneuploidy). The input values were the degree of aneuploidy (initially set at 3 per chromosome for sporadic aneuploidy) and the accuracy per probe (initially set at 95), defined as the proportion of normal diploid nuclei with a normal signal pattern. The primary statistic was the predictive value of the test result. RESULTS: Testing two chromosome pairs to determine sex chromosome status or detect unbalanced translocation products had high predictive value: at least 99.5 for a normal test result (95 CI: 99-100), and 90 for an abnormal test result (95 CI: 88-92). However, the predictive value of an abnormal test result testing five chromosomes for sporadic chromosome aneuploidy was 41 (95 CI: 36-46); 90 would be achieved with an aneuploidy rate per chromosome of 20.3 (equivalent to 99.5 prevalence for 23 chromosomes) rather than 3, or with an accuracy per probe of 99.6 rather than 95, or when testing 23 chromosome pairs, rather than 5 pairs, with either 8.3 aneuploidy (86.4 prevalence) or 99.5 accuracy. CONCLUSIONS: Testing a single cell using the FISH technique has the potential to achieve acceptable analytical performance for sex determination and two-way reciprocal translocations, but is unlikely to achieve adequate performance testing for sporadic chromosome aneuploidy. New techniques for detecting the copy number of every chromosome are emerging, but it remains to be seen if the high accuracy required will be achieved. © 2010 The Author. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved.

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