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Validation of a Custom Next-Generation Sequencing Assay for Cystic Fibrosis Newborn Screening. Int J Neonatal Screen 2021; 7:ijns7040073. [PMID: 34842611 PMCID: PMC8628990 DOI: 10.3390/ijns7040073] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/20/2021] [Accepted: 10/28/2021] [Indexed: 11/16/2022] Open
Abstract
Newborn screening (NBS) for Cystic Fibrosis (CF) is associated with improved outcomes. All US states screen for CF; however, CF NBS algorithms have high false positive (FP) rates. In New York State (NYS), the positive predictive value of CF NBS improved from 3.7% to 25.2% following the implementation of a three-tier IRT-DNA-SEQ approach using commercially available tests. Here we describe a modification of the NYS CF NBS algorithm via transition to a new custom next-generation sequencing (NGS) platform for more comprehensive cystic fibrosis transmembrane conductance regulator (CFTR) gene analysis. After full gene sequencing, a tiered strategy is used to first analyze only a specific panel of 338 clinically relevant CFTR variants (second-tier), followed by unblinding of all sequence variants and bioinformatic assessment of deletions/duplications in a subset of samples requiring third-tier analysis. We demonstrate the analytical and clinical validity of the assay and the feasibility of use in the NBS setting. The custom assay has streamlined our molecular workflow, increased throughput, and allows for bioinformatic customization of second-tier variant panel content. NBS aims to identify those infants with the highest disease risk. Technological molecular improvements can be applied to NBS algorithms to reduce the burden of FP referrals without loss of sensitivity.
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Claustres M, Thèze C, des Georges M, Baux D, Girodon E, Bienvenu T, Audrezet MP, Dugueperoux I, Férec C, Lalau G, Pagin A, Kitzis A, Thoreau V, Gaston V, Bieth E, Malinge MC, Reboul MP, Fergelot P, Lemonnier L, Mekki C, Fanen P, Bergougnoux A, Sasorith S, Raynal C, Bareil C. CFTR-France, a national relational patient database for sharing genetic and phenotypic data associated with rare CFTR variants. Hum Mutat 2017; 38:1297-1315. [PMID: 28603918 DOI: 10.1002/humu.23276] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/31/2017] [Accepted: 06/04/2017] [Indexed: 11/09/2022]
Abstract
Most of the 2,000 variants identified in the CFTR (cystic fibrosis transmembrane regulator) gene are rare or private. Their interpretation is hampered by the lack of available data and resources, making patient care and genetic counseling challenging. We developed a patient-based database dedicated to the annotations of rare CFTR variants in the context of their cis- and trans-allelic combinations. Based on almost 30 years of experience of CFTR testing, CFTR-France (https://cftr.iurc.montp.inserm.fr/cftr) currently compiles 16,819 variant records from 4,615 individuals with cystic fibrosis (CF) or CFTR-RD (related disorders), fetuses with ultrasound bowel anomalies, newborns awaiting clinical diagnosis, and asymptomatic compound heterozygotes. For each of the 736 different variants reported in the database, patient characteristics and genetic information (other variations in cis or in trans) have been thoroughly checked by a dedicated curator. Combining updated clinical, epidemiological, in silico, or in vitro functional data helps to the interpretation of unclassified and the reassessment of misclassified variants. This comprehensive CFTR database is now an invaluable tool for diagnostic laboratories gathering information on rare variants, especially in the context of genetic counseling, prenatal and preimplantation genetic diagnosis. CFTR-France is thus highly complementary to the international database CFTR2 focused so far on the most common CF-causing alleles.
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Affiliation(s)
- Mireille Claustres
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire et Université de Montpellier, Montpellier, France
| | - Corinne Thèze
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire et Université de Montpellier, Montpellier, France
| | - Marie des Georges
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire et Université de Montpellier, Montpellier, France
| | - David Baux
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire et Université de Montpellier, Montpellier, France
| | - Emmanuelle Girodon
- Service de Génétique et Biologie Moléculaires, Groupe Hospitalier Cochin-Broca-Hotel Dieu, Paris, France
| | - Thierry Bienvenu
- Service de Génétique et Biologie Moléculaires, Groupe Hospitalier Cochin-Broca-Hotel Dieu, Paris, France
| | - Marie-Pierre Audrezet
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Centre Hospitalier Régional Universitaire, Brest, France
| | - Ingrid Dugueperoux
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Centre Hospitalier Régional Universitaire, Brest, France
| | - Claude Férec
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Centre Hospitalier Régional Universitaire, Brest, France
| | - Guy Lalau
- Centre de Biologie Pathologie Génétique, Centre Hospitalier Régional Universitaire, Lille, France
| | - Adrien Pagin
- Centre de Biologie Pathologie Génétique, Centre Hospitalier Régional Universitaire, Lille, France
| | - Alain Kitzis
- Département de Génétique, Centre Hospitalier Universitaire, Poitiers, France
| | - Vincent Thoreau
- Département de Génétique, Centre Hospitalier Universitaire, Poitiers, France
| | - Véronique Gaston
- Service de Génétique Médicale, Centre Hospitalier Universitaire, Toulouse, France
| | - Eric Bieth
- Service de Génétique Médicale, Centre Hospitalier Universitaire, Toulouse, France
| | - Marie-Claire Malinge
- Département de Biochimie Génétique, Institut de Biologie en Santé, Centre Hospitalier Universitaire, Angers, France
| | - Marie-Pierre Reboul
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Régional Universitaire, Bordeaux, France
| | - Patricia Fergelot
- Laboratoire Maladies Rares, Génétique et Métabolisme, Bordeaux, France
| | - Lydie Lemonnier
- Registre français de la mucoviscidose, Vaincre la Mucoviscidose, Paris, France
| | - Chadia Mekki
- Laboratoire de Génétique, Hôpital Henri Mondor, Créteil, France
| | - Pascale Fanen
- Laboratoire de Génétique, Hôpital Henri Mondor, Créteil, France
| | - Anne Bergougnoux
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire et Université de Montpellier, Montpellier, France
| | - Souphatta Sasorith
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire et Université de Montpellier, Montpellier, France
| | - Caroline Raynal
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire et Université de Montpellier, Montpellier, France
| | - Corinne Bareil
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire et Université de Montpellier, Montpellier, France
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Schrijver I, Rappahahn K, Pique L, Kharrazi M, Wong LJ. Multiplex ligation-dependent probe amplification identification of whole exon and single nucleotide deletions in the CFTR gene of Hispanic individuals with cystic fibrosis. J Mol Diagn 2008; 10:368-75. [PMID: 18556774 DOI: 10.2353/jmoldx.2008.080004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
A disparity between Caucasian and Hispanic mutation detection for cystic fibrosis continues to exist, although the carrier frequency is only moderately lower in Hispanics. We aimed to identify exonic rearrangements that remained undetected by conventional methods. In seven of 32 cystic fibrosis-affected self-identified Hispanics for whom only one or no mutations were identified by extensive molecular testing, exon deletions appeared to be present with a multiplex ligation-dependent probe amplification (MLPA) assay. Two recurrent deletions (of exons 2-3 and exons 22-23) were identified in one and three patients, respectively (12.5%, 11.1% of unidentified alleles). Two apparently novel deletions (exons 6b and 20) were identified in three additional patients. Subsequent sequencing to characterize deletion breakpoints, however, identified single nucleotide deletions at the probe binding sites close to the ligation point. All resulted in false positive MLPA deletion signals. Interestingly, these mutations were not common in Caucasians, and one (935delA) was common in U.S. Hispanics. On examination of all probe binding sites, we identified a total of 76 reported mutations and five silent variants that immediately surrounded the MLPA ligation sites, with 22 occurring in non-Caucasians. These mutations are not all rare. Thus, apparent exon deletions by MLPA may indicate the presence of both large deletions and point mutations, with important implications for pan-ethnic MLPA testing in cystic fibrosis and other genetic conditions.
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Affiliation(s)
- Iris Schrijver
- Department of Pathology L235, Stanford University Medical Center, 300 Pasteur Drive, Stanford, CA 94305, USA.
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Chen JM, Masson E, Macek M, Raguénès O, Piskackova T, Fercot B, Fila L, Cooper DN, Audrézet MP, Férec C. Detection of two Alu insertions in the CFTR gene. J Cyst Fibros 2007; 7:37-43. [PMID: 17531547 DOI: 10.1016/j.jcf.2007.04.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Revised: 04/12/2007] [Accepted: 04/13/2007] [Indexed: 01/08/2023]
Abstract
BACKGROUND LINE-1 (long interspersed element-1) or L1-mediated retrotransposition is a potent force in human genome evolution and an occasional cause of human genetic disease. Since the first report of two de novo L1 insertions in the F8 gene causing hemophilia A, more than 50 L1-mediated retrotranspositional events have been identified as causing human genetic disease. However, a significant bias has generally militated against the detection of these pathological events at autosomal loci. Based upon this and other observations, we surmised that some previously unresolved cystic fibrosis chromosomes might carry hitherto undetected L1-mediated retrotranspositional insertions at the CFTR locus. This study represents an attempt to identify such mutational events. METHODS 100 previously unresolved cystic fibrosis chromosomes were carefully reanalyzed using quantitative high-performance liquid chromatography (QHPLC). RESULTS Two simple Alu insertions were identified in the CFTR gene, within exons 16 and 17b respectively. CONCLUSIONS Our findings have not only revealed a previously unknown mutational mechanism responsible for cystic fibrosis but also represent an important addition to the already diverse spectrum of known CFTR gene mutations. Experience with the CFTR gene suggests that pathological L1-mediated retrotranspositional events may also have been overlooked at other gene loci and should always be considered in cases that appear to be refractory to analysis.
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