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De Paolis E, Tilocca B, Lombardi C, De Bonis M, Concolino P, Onori ME, Ricciardi Tenore C, Perrucci A, Roncada P, Capoluongo E, Urbani A, Minucci A, Santonocito C. Next-Generation Sequencing for Screening Analysis of Cystic Fibrosis: Spectrum and Novel Variants in a South-Central Italian Cohort. Genes (Basel) 2023; 14:1608. [PMID: 37628659 PMCID: PMC10454170 DOI: 10.3390/genes14081608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 08/06/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
The incidence of cystic fibrosis (CF) and the spectrum of cystic fibrosis transmembrane conductance regulator (CFTR) gene variants differ among geographic regions. Differences in CF carrier distribution are also reported among Italian regions. We described the spectrum of the CFTR variants observed in a large group of subjects belonging from central-southern Italy. We also provide a predictive evaluation of the novel variants identified. CFTR screening was performed in a south-central Italian cohort of 770 subjects. We adopted a next-generation sequencing (NGS) approach using the Devyser CFTR NGS kit on the Illumina MiSeq System coupled with Amplicon Suite data analysis. Bioinformatics evaluation of the impact of novel variants was described. Overall, the presence of at least one alternative allele in the CFTR gene was recorded for 23% of the subjects, with a carrier frequency of CF pathogenic variants of 1:12. The largest sub-group corresponded to the heterozygous carriers of a variant with a conflicting interpretation of pathogenicity. The common CFTR p.(Phe508del) pathogenic variants were identified in 37% of mutated subjects. Bioinformatics prediction supported a potential damaging effect for the three novel CFTR variants identified: p.(Leu1187Phe), p.(Pro22Thr), and c.744-3C > G. NGS applied to CF screening had the benefit of: effectively identifying asymptomatic carriers. It lies in a wide overview of CFTR variants and gives a comprehensive picture of the carrier prevalence. The identification of a high number of unclassified variants may represent a challenge whilst at the same time being of interest and relevance for clinicians.
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Affiliation(s)
- Elisa De Paolis
- Departmental Unit of Molecular and Genomic Diagnostics, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.D.P.); (M.D.B.); (M.E.O.); (C.R.T.); (A.P.); (A.U.); (A.M.)
- Department of Basic Biotechnological Sciences, Intensivological and Perioperative Clinics, Catholic University of Sacred Heart, 00168 Rome, Italy;
| | - Bruno Tilocca
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (B.T.); (P.R.)
| | - Carla Lombardi
- Department of Basic Biotechnological Sciences, Intensivological and Perioperative Clinics, Catholic University of Sacred Heart, 00168 Rome, Italy;
| | - Maria De Bonis
- Departmental Unit of Molecular and Genomic Diagnostics, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.D.P.); (M.D.B.); (M.E.O.); (C.R.T.); (A.P.); (A.U.); (A.M.)
| | - Paola Concolino
- Departmental Unit of Molecular and Genomic Diagnostics, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.D.P.); (M.D.B.); (M.E.O.); (C.R.T.); (A.P.); (A.U.); (A.M.)
| | - Maria Elisabetta Onori
- Departmental Unit of Molecular and Genomic Diagnostics, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.D.P.); (M.D.B.); (M.E.O.); (C.R.T.); (A.P.); (A.U.); (A.M.)
| | - Claudio Ricciardi Tenore
- Departmental Unit of Molecular and Genomic Diagnostics, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.D.P.); (M.D.B.); (M.E.O.); (C.R.T.); (A.P.); (A.U.); (A.M.)
| | - Alessia Perrucci
- Departmental Unit of Molecular and Genomic Diagnostics, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.D.P.); (M.D.B.); (M.E.O.); (C.R.T.); (A.P.); (A.U.); (A.M.)
| | - Paola Roncada
- Department of Health Science, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (B.T.); (P.R.)
| | - Ettore Capoluongo
- Department of Molecular Medicine and Medical Biotechnologies, University Federico II, 80138 Naples, Italy;
- Department of Clinical Pathology and Genomics, Ospedale Cannizzaro, 95021 Catania, Italy
| | - Andrea Urbani
- Departmental Unit of Molecular and Genomic Diagnostics, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.D.P.); (M.D.B.); (M.E.O.); (C.R.T.); (A.P.); (A.U.); (A.M.)
- Department of Basic Biotechnological Sciences, Intensivological and Perioperative Clinics, Catholic University of Sacred Heart, 00168 Rome, Italy;
| | - Angelo Minucci
- Departmental Unit of Molecular and Genomic Diagnostics, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.D.P.); (M.D.B.); (M.E.O.); (C.R.T.); (A.P.); (A.U.); (A.M.)
| | - Concetta Santonocito
- Departmental Unit of Molecular and Genomic Diagnostics, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.D.P.); (M.D.B.); (M.E.O.); (C.R.T.); (A.P.); (A.U.); (A.M.)
- Department of Basic Biotechnological Sciences, Intensivological and Perioperative Clinics, Catholic University of Sacred Heart, 00168 Rome, Italy;
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Bergougnoux A, Billet A, Ka C, Heller M, Degrugillier F, Vuillaume ML, Thoreau V, Sasorith S, Bareil C, Thèze C, Ferec C, Gac GL, Bienvenu T, Bieth E, Gaston V, Lalau G, Pagin A, Malinge MC, Dufernez F, Lemonnier L, Koenig M, Fergelot P, Claustres M, Taulan-Cadars M, Kitzis A, Reboul MP, Becq F, Fanen P, Mekki C, Audrezet MP, Girodon E, Raynal C. The multi-faceted nature of 15 CFTR exonic variations: Impact on their functional classification and perspectives for therapy. J Cyst Fibros 2022:S1569-1993(22)01423-0. [PMID: 36567205 DOI: 10.1016/j.jcf.2022.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 09/30/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022]
Abstract
BACKGROUND The majority of variants of unknown clinical significance (VUCS) in the CFTR gene are missense variants. While change on the CFTR protein structure or function is often suspected, impact on splicing may be neglected. Such undetected splicing default of variants may complicate the interpretation of genetic analyses and the use of an appropriate pharmacotherapy. METHODS We selected 15 variants suspected to impact CFTR splicing after in silico predictions on 319 missense variants (214 VUCS), reported in the CFTR-France database. Six specialized laboratories assessed the impact of nucleotide substitutions on splicing (minigenes), mRNA expression levels (quantitative PCR), synthesis and maturation (western blot), cellular localization (immunofluorescence) and channel function (patch clamp) of the CFTR protein. We also studied maturation and function of the truncated protein, consecutive to in-frame aberrant splicing, on additional plasmid constructs. RESULTS Six of the 15 variants had a major impact on CFTR splicing by in-frame (n = 3) or out-of-frame (n = 3) exon skipping. We reclassified variants into: splicing variants; variants causing a splicing defect and the impairment of CFTR folding and/or function related to the amino acid substitution; deleterious missense variants that impair CFTR folding and/or function; and variants with no consequence on the different processes tested. CONCLUSION The 15 variants have been reclassified by our comprehensive approach of in vitro experiments that should be used to properly interpret very rare exonic variants of the CFTR gene. Targeted therapies may thus be adapted to the molecular defects regarding the results of laboratory experiments.
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Affiliation(s)
- A Bergougnoux
- Génétique Moléculaire, CHU Montpellier, Montpellier, France; PhyMedExp, INSERM, CNRS UMR, Montpellier, France; Université de Montpellier, Montpellier, France
| | - A Billet
- Laboratoire STIM, Université de Poitiers, Poitiers, France
| | - C Ka
- Service de génétique moléculaire, CHRU Brest, Brest, France; Université de Brest, Inserm, UMR 1078, GGB, Brest, France
| | - M Heller
- Service de Médecine Génomique des Maladies de Système et d'Organe, APHP Centre - Université de Paris, Hôpital Cochin, Paris, France
| | - F Degrugillier
- Université Paris-Est Créteil, INSERM, IMRB, Créteil F-94010, France
| | - M-L Vuillaume
- Génétique Moléculaire, CHU Bordeaux, Bordeaux, France
| | - V Thoreau
- Laboratoire NEUVACOD-3808, Université de Poitiers, Poitiers, France
| | - S Sasorith
- Génétique Moléculaire, CHU Montpellier, Montpellier, France; PhyMedExp, INSERM, CNRS UMR, Montpellier, France
| | - C Bareil
- Génétique Moléculaire, CHU Montpellier, Montpellier, France
| | - C Thèze
- Génétique Moléculaire, CHU Montpellier, Montpellier, France
| | - C Ferec
- Université de Brest, Inserm, UMR 1078, GGB, Brest, France
| | - G Le Gac
- Service de génétique moléculaire, CHRU Brest, Brest, France; Université de Brest, Inserm, UMR 1078, GGB, Brest, France
| | - T Bienvenu
- Service de Médecine Génomique des Maladies de Système et d'Organe, APHP Centre - Université de Paris, Hôpital Cochin, Paris, France
| | - E Bieth
- Génétique Médicale, CHU Toulouse, Toulouse, France
| | - V Gaston
- Génétique Médicale, CHU Toulouse, Toulouse, France
| | - G Lalau
- Biochimie et Biologie Moléculaire, CHU Lille, Lille, France
| | - A Pagin
- Biochimie et Biologie Moléculaire, CHU Lille, Lille, France
| | - M-C Malinge
- Biochimie et Génétique, CHU Angers, Angers, France
| | - F Dufernez
- Génétique, CHU Poitiers, Poitiers, France
| | - L Lemonnier
- Association Vaincre la Mucoviscidose, Paris, France
| | - M Koenig
- Génétique Moléculaire, CHU Montpellier, Montpellier, France; PhyMedExp, INSERM, CNRS UMR, Montpellier, France; Université de Montpellier, Montpellier, France
| | - P Fergelot
- MRGM, INSERM UMR 1211 Université de Bordeaux, Bordeaux, France
| | - M Claustres
- Université de Montpellier, Montpellier, France
| | - M Taulan-Cadars
- PhyMedExp, INSERM, CNRS UMR, Montpellier, France; Université de Montpellier, Montpellier, France
| | - A Kitzis
- Génétique, CHU Poitiers, Poitiers, France
| | - M-P Reboul
- Génétique Moléculaire, CHU Bordeaux, Bordeaux, France
| | - F Becq
- Laboratoire STIM, Université de Poitiers, Poitiers, France
| | - P Fanen
- AP-HP, Département de Biochimie-Biologie Moléculaire, Pharmacologie, Génétique Médicale, Hôpital Henri Mondor, Créteil F-94010, France
| | - C Mekki
- AP-HP, Département de Biochimie-Biologie Moléculaire, Pharmacologie, Génétique Médicale, Hôpital Henri Mondor, Créteil F-94010, France
| | - M-P Audrezet
- Service de génétique moléculaire, CHRU Brest, Brest, France; Université de Brest, Inserm, UMR 1078, GGB, Brest, France
| | - E Girodon
- Service de Médecine Génomique des Maladies de Système et d'Organe, APHP Centre - Université de Paris, Hôpital Cochin, Paris, France; INSERM U1151, Institut Necker Enfants Malades, Université de Paris, Paris, France
| | - C Raynal
- Génétique Moléculaire, CHU Montpellier, Montpellier, France; PhyMedExp, INSERM, CNRS UMR, Montpellier, France.
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Hatton A, Bergougnoux A, Zybert K, Chevalier B, Mesbahi M, Altéri JP, Walicka-Serzysko K, Postek M, Taulan-Cadars M, Edelman A, Hinzpeter A, Claustres M, Girodon E, Raynal C, Sermet-Gaudelus I, Sands D. Reclassifying inconclusive diagnosis after newborn screening for cystic fibrosis. Moving forward. J Cyst Fibros 2021; 21:448-455. [PMID: 34949556 DOI: 10.1016/j.jcf.2021.12.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND Newborn screening for Cystic Fibrosis (CF) is associated with situations where the diagnosis of CF or CFTR related disorders (CFTR-RD) cannot be clearly ruled out. MATERIALS/PATIENTS AND METHODS We report a case series of 23 children with unconclusive diagnosis after newborn screening for CF and a mean follow-up of 7.7 years (4-13). Comprehensive investigations including whole CFTR gene sequencing, in vivo intestinal current measurement (ICM), nasal potential difference (NPD), and in vitro functional studies of variants of unknown significance, helped to reclassify the patients. RESULTS Extensive genetic testing identified, in trans with a CF causing mutation, variants with varying clinical consequences and 3 variants of unknown significance (VUS). Eighteen deep intronic variants were identified by deep resequencing of the whole CFTR gene in 13 patients and were finally considered as non-pathogenic. All patients had normal CFTR dependent chloride transport in ICM. NPD differentiated 3 different profiles: CF-like tracings qualifying the patients as CF, such as F508del/D1152H patients; normal responses, suggesting an extremely low likelihood of developing a CFTR-RD such as F508del/TG11T5 patients; partial CFTR dysfunction above 20% of the normal, highlighting a remaining risk of developing CFTR-RD such as F508del/F1052V patients. The 3 VUS were reclassified as variant with defective maturation (D537N), defective expression (T582I) or with no clinical consequence (M952T). CONCLUSION This study demonstrates the usefulness of combining genetic and functional investigations to assess the possibility of evolving to CF or CFTR-RD in babies with inconclusive diagnosis at neonatal screening.
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Affiliation(s)
- Aurelie Hatton
- INSERM U1151, Institut Necker Enfants Malades, Université de Paris, 149 rue de Sévres, Paris 75015, France; Université de Paris, Paris, France
| | - Anne Bergougnoux
- PhyMedExp, INSERM U1046, CNRS UMR 9214, University of Montpellier, Montpellier, France; CHU de Montpellier, Laboratoire de Génétique Moléculaire, Montpellier, France
| | - Katarzyna Zybert
- Cystic Fibrosis Department, Institute of Mother and Child, Warsaw, Poland
| | - Benoit Chevalier
- INSERM U1151, Institut Necker Enfants Malades, Université de Paris, 149 rue de Sévres, Paris 75015, France; Université de Paris, Paris, France
| | - Myriam Mesbahi
- INSERM U1151, Institut Necker Enfants Malades, Université de Paris, 149 rue de Sévres, Paris 75015, France; Université de Paris, Paris, France
| | - Jean Pierre Altéri
- CHU de Montpellier, Laboratoire de Génétique Moléculaire, Montpellier, France
| | | | - Magdalena Postek
- Cystic Fibrosis Department, Institute of Mother and Child, Warsaw, Poland
| | - Magali Taulan-Cadars
- PhyMedExp, INSERM U1046, CNRS UMR 9214, University of Montpellier, Montpellier, France; Université de Montpellier, Montpellier, France
| | - Aleksander Edelman
- INSERM U1151, Institut Necker Enfants Malades, Université de Paris, 149 rue de Sévres, Paris 75015, France; Université de Paris, Paris, France
| | - Alexandre Hinzpeter
- INSERM U1151, Institut Necker Enfants Malades, Université de Paris, 149 rue de Sévres, Paris 75015, France; Université de Paris, Paris, France
| | | | - Emmanuelle Girodon
- INSERM U1151, Institut Necker Enfants Malades, Université de Paris, 149 rue de Sévres, Paris 75015, France; Laboratoire de Génétique et Biologie Moléculaires, Hôpital Cochin, APHP Centre, Université de Paris, Paris, France
| | - Caroline Raynal
- PhyMedExp, INSERM U1046, CNRS UMR 9214, University of Montpellier, Montpellier, France; CHU de Montpellier, Laboratoire de Génétique Moléculaire, Montpellier, France
| | - Isabelle Sermet-Gaudelus
- INSERM U1151, Institut Necker Enfants Malades, Université de Paris, 149 rue de Sévres, Paris 75015, France; Université de Paris, Paris, France; Centre de Référence Maladies Rares, Mucoviscidose et maladies apparentées, Hôpital Necker Enfants Malades, Paris, France; European Reference Network-Lung, France.
| | - Dorota Sands
- Cystic Fibrosis Department, Institute of Mother and Child, Warsaw, Poland
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