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Bonetti G, Cozza W, Bernini A, Kaftalli J, Mareso C, Cristofoli F, Medori MC, Colombo L, Martella S, Staurenghi G, Salvetti AP, Falsini B, Placidi G, Attanasio M, Pertile G, Bengala M, Bosello F, Petracca A, D’Esposito F, Toschi B, Lanzetta P, Ricci F, Viola F, Marceddu G, Bertelli M. Towards a Long-Read Sequencing Approach for the Molecular Diagnosis of RPGR ORF15 Genetic Variants. Int J Mol Sci 2023; 24:16881. [PMID: 38069202 PMCID: PMC10706286 DOI: 10.3390/ijms242316881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/17/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Sequencing of the low-complexity ORF15 exon of RPGR, a gene correlated with retinitis pigmentosa and cone dystrophy, is difficult to achieve with NGS and Sanger sequencing. False results could lead to the inaccurate annotation of genetic variants in dbSNP and ClinVar databases, tools on which HGMD and Ensembl rely, finally resulting in incorrect genetic variants interpretation. This paper aims to propose PacBio sequencing as a feasible method to correctly detect genetic variants in low-complexity regions, such as the ORF15 exon of RPGR, and interpret their pathogenicity by structural studies. Biological samples from 75 patients affected by retinitis pigmentosa or cone dystrophy were analyzed with NGS and repeated with PacBio. The results showed that NGS has a low coverage of the ORF15 region, while PacBio was able to sequence the region of interest and detect eight genetic variants, of which four are likely pathogenic. Furthermore, molecular modeling and dynamics of the RPGR Glu-Gly repeats binding to TTLL5 allowed for the structural evaluation of the variants, providing a way to predict their pathogenicity. Therefore, we propose PacBio sequencing as a standard procedure in diagnostic research for sequencing low-complexity regions such as RPGRORF15, aiding in the correct annotation of genetic variants in online databases.
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Affiliation(s)
- Gabriele Bonetti
- MAGI’s LAB, 38068 Rovereto, Italy; (M.C.M.); (M.B.)
- Department of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
| | - William Cozza
- MAGI Euregio, 39100 Bolzano, Italy; (W.C.); (J.K.); (C.M.); (F.D.); (G.M.)
| | - Andrea Bernini
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100 Siena, Italy;
| | - Jurgen Kaftalli
- MAGI Euregio, 39100 Bolzano, Italy; (W.C.); (J.K.); (C.M.); (F.D.); (G.M.)
| | - Chiara Mareso
- MAGI Euregio, 39100 Bolzano, Italy; (W.C.); (J.K.); (C.M.); (F.D.); (G.M.)
| | | | | | - Leonardo Colombo
- Department of Ophthalmology, ASST Santi Paolo e Carlo Hospital, University of Milan, 20142 Milan, Italy; (L.C.); (S.M.)
| | - Salvatore Martella
- Department of Ophthalmology, ASST Santi Paolo e Carlo Hospital, University of Milan, 20142 Milan, Italy; (L.C.); (S.M.)
| | - Giovanni Staurenghi
- Eye Clinic, Department of Biomedical and Clinical Science, Luigi Sacco Hospital, University of Milan, 20157 Milan, Italy; (G.S.); (A.P.S.)
| | - Anna Paola Salvetti
- Eye Clinic, Department of Biomedical and Clinical Science, Luigi Sacco Hospital, University of Milan, 20157 Milan, Italy; (G.S.); (A.P.S.)
| | - Benedetto Falsini
- UOC Oculistica, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, Largo Gemelli 8, 00168 Rome, Italy (G.P.)
- Istituto di Oftalmologia, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy
| | - Giorgio Placidi
- UOC Oculistica, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, Largo Gemelli 8, 00168 Rome, Italy (G.P.)
| | - Marcella Attanasio
- Ospedale Sacrocuore Don Calabria, Viale Luigi Rizzardi, 4, 37024 Negrar di Valpolicella, Italy; (M.A.); (G.P.)
| | - Grazia Pertile
- Ospedale Sacrocuore Don Calabria, Viale Luigi Rizzardi, 4, 37024 Negrar di Valpolicella, Italy; (M.A.); (G.P.)
| | - Mario Bengala
- Medical Genetics Unit, Department of Oncohematology, Policlinico Tor Vergata, 00133 Rome, Italy;
| | - Francesca Bosello
- Department of Surgical Sciences, Dentistry, Paediatrics and Gynaecology, Section of Ophthalmology, University of Verona, 37134 Verona, Italy;
| | - Antonio Petracca
- Division of Medical Genetics, Fondazione IRCCS-Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy;
| | - Fabiana D’Esposito
- MAGI Euregio, 39100 Bolzano, Italy; (W.C.); (J.K.); (C.M.); (F.D.); (G.M.)
- Imperial College Ophthalmic Research Group (ICORG) Unit, Imperial College, London NW1 5QH, UK
- Eye Clinic, Department of Neurosciences, Reproductive Sciences and Dentistry, University of Naples Federico II, 80138 Naples, Italy
| | - Benedetta Toschi
- Section of Medical Genetics, Department of Medical and Oncological Area, University Hospital of Pisa, 56126 Pisa, Italy;
| | - Paolo Lanzetta
- Department of Medicine-Ophthalmology, University of Udine, 33100 Udine, Italy;
- Istituto Europeo di Microchirurgia Oculare (IEMO), 33100 Udine, Italy
| | - Federico Ricci
- Department of Experimental Medicine, Tor Vergata University of Rome, Viale Oxford, 00133 Rome, Italy;
| | - Francesco Viola
- Department of Ophthalmology, Fondazione IRCCS Cà Granda, Clinica Regina Elena, 20122 Milan, Italy;
| | - Giuseppe Marceddu
- MAGI Euregio, 39100 Bolzano, Italy; (W.C.); (J.K.); (C.M.); (F.D.); (G.M.)
| | - Matteo Bertelli
- MAGI’s LAB, 38068 Rovereto, Italy; (M.C.M.); (M.B.)
- MAGI Euregio, 39100 Bolzano, Italy; (W.C.); (J.K.); (C.M.); (F.D.); (G.M.)
- MAGISNAT, Atlanta Tech Park, 107 Technology Parkway, Peachtree Corners, GA 30092, USA
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Pachchek S, Landoulsi Z, Pavelka L, Schulte C, Buena-Atienza E, Gross C, Hauser AK, Reddy Bobbili D, Casadei N, May P, Krüger R. Accurate long-read sequencing identified GBA1 as major risk factor in the Luxembourgish Parkinson's study. NPJ Parkinsons Dis 2023; 9:156. [PMID: 37996455 PMCID: PMC10667262 DOI: 10.1038/s41531-023-00595-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 10/24/2023] [Indexed: 11/25/2023] Open
Abstract
Heterozygous variants in the glucocerebrosidase GBA1 gene are an increasingly recognized risk factor for Parkinson's disease (PD). Due to the GBAP1 pseudogene, which shares 96% sequence homology with the GBA1 coding region, accurate variant calling by array-based or short-read sequencing methods remains a major challenge in understanding the genetic landscape of GBA1-associated PD. We analyzed 660 patients with PD, 100 patients with Parkinsonism and 808 healthy controls from the Luxembourg Parkinson's study, sequenced using amplicon-based long-read DNA sequencing technology. We found that 12.1% (77/637) of PD patients carried GBA1 variants, with 10.5% (67/637) of them carrying known pathogenic variants (including severe, mild, risk variants). In comparison, 5% (34/675) of the healthy controls carried GBA1 variants, and among them, 4.3% (29/675) were identified as pathogenic variant carriers. We found four GBA1 variants in patients with atypical parkinsonism. Pathogenic GBA1 variants were 2.6-fold more frequently observed in PD patients compared to controls (OR = 2.6; CI = [1.6,4.1]). Three novel variants of unknown significance (VUS) were identified. Using a structure-based approach, we defined a potential risk prediction method for VUS. This study describes the full landscape of GBA1-related parkinsonism in Luxembourg, showing a high prevalence of GBA1 variants as the major genetic risk for PD. Although the long-read DNA sequencing technique used in our study may be limited in its effectiveness to detect potential structural variants, our approach provides an important advancement for highly accurate GBA1 variant calling, which is essential for providing access to emerging causative therapies for GBA1 carriers.
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Grants
- FNR/NCER13/BM/11264123 Fonds National de la Recherche Luxembourg (National Research Fund)
- funded by the Luxembourg National Research (FNR/NCER13/BM/11264123), the PEARL program (FNR/P13/6682797 to RK), MotaSYN (12719684 to RK), MAMaSyn (to RK), MiRisk‐PD (C17/BM/11676395 to RK, PM), the FNR/DFG Core INTER (ProtectMove, FNR11250962 to PM), and the PARK-QC DTU (PRIDE17/12244779/PARK-QC to RK, SP)
- Luxembourg National Research Fund (FNR/NCER13/BM/11264123), the PEARL program (FNR/P13/6682797), MotaSYN (12719684), MAMaSyn, MiRisk‐PD (C17/BM/11676395), and the PARK-QC DTU (PRIDE17/12244779/PARK-QC)
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Affiliation(s)
- Sinthuja Pachchek
- LCSB, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-Sur-Alzette, Luxembourg.
| | - Zied Landoulsi
- LCSB, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-Sur-Alzette, Luxembourg
| | - Lukas Pavelka
- Parkinson Research Clinic, Centre Hospitalier de Luxembourg (CHL), Luxembourg, Luxembourg
- Transversal Translational Medicine, Luxembourg Institute of Health (LIH), Strassen, Luxembourg
| | - Claudia Schulte
- Department of Neurodegeneration, Center of Neurology, Hertie Institute for Clinical Brain Research, German Center for Neurodegenerative Diseases, University of Tübingen, Tübingen, Germany
| | - Elena Buena-Atienza
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen (NCCT), University of Tübingen, Tübingen, Germany
| | - Caspar Gross
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen (NCCT), University of Tübingen, Tübingen, Germany
| | - Ann-Kathrin Hauser
- Department of Neurodegeneration, Center of Neurology, Hertie Institute for Clinical Brain Research, German Center for Neurodegenerative Diseases, University of Tübingen, Tübingen, Germany
| | - Dheeraj Reddy Bobbili
- LCSB, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-Sur-Alzette, Luxembourg
| | - Nicolas Casadei
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen (NCCT), University of Tübingen, Tübingen, Germany
| | - Patrick May
- LCSB, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-Sur-Alzette, Luxembourg.
| | - Rejko Krüger
- LCSB, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-Sur-Alzette, Luxembourg.
- Parkinson Research Clinic, Centre Hospitalier de Luxembourg (CHL), Luxembourg, Luxembourg.
- Transversal Translational Medicine, Luxembourg Institute of Health (LIH), Strassen, Luxembourg.
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Optimization of long-range PCR protocol to prepare filaggrin exon 3 libraries for PacBio long-read sequencing. Mol Biol Rep 2023; 50:3119-3127. [PMID: 36692677 PMCID: PMC10042914 DOI: 10.1007/s11033-022-08170-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 12/01/2022] [Indexed: 01/25/2023]
Abstract
BACKGROUND The filaggrin (FLG) protein, encoded by the FLG gene, is an intermediate filament-associated protein that plays a crucial role in the terminal stages of human epidermal differentiation. Loss-of-function mutations in the FLG exon 3 have been associated with skin diseases. The identification of causative mutations is challenging, due to the high sequence homology within its exon 3 (12,753 bp), which includes 10 to 12 filaggrin tandem repeats. With this study we aimed to obtain the whole FLG exon 3 sequence through PacBio technology, once 13-kb amplicons have been generated. METHODS AND RESULTS For the preparation of SMRTbell libraries to be sequenced using PacBio technology, we focused on optimizing a 2-step long-range PCR protocol to generate 13-kb amplicons covering the whole FLG exon 3 sequence. The performance of three long-range DNA polymerases was assessed in an attempt to improve the PCR conditions required for the enzymes to function properly. We focused on optimization of the input template DNA concentration and thermocycling parameters to correctly amplify the entire FLG exon 3 sequence, minimizing non-specific amplification. CONCLUSIONS Taken together, our findings suggested that the PrimeSTAR protocol is suitable for producing the amplicons of the 13-kb FLG whole exon 3 to prepare SMRTbell libraries. We suggest that sequencing the generated amplicons may be useful for identifying LoF variants that are causative of the patients' disorders.
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Fernandez G, Yubero D, Palau F, Armstrong J. Molecular Modelling Hurdle in the Next-Generation Sequencing Era. Int J Mol Sci 2022; 23:ijms23137176. [PMID: 35806177 PMCID: PMC9266691 DOI: 10.3390/ijms23137176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 06/24/2022] [Accepted: 06/27/2022] [Indexed: 12/10/2022] Open
Abstract
There are challenges in the genetic diagnosis of rare diseases, and pursuing an optimal strategy to identify the cause of the disease is one of the main objectives of any clinical genomics unit. A range of techniques are currently used to characterize the genomic variability within the human genome to detect causative variants of specific disorders. With the introduction of next-generation sequencing (NGS) in the clinical setting, geneticists can study single-nucleotide variants (SNVs) throughout the entire exome/genome. In turn, the number of variants to be evaluated per patient has increased significantly, and more information has to be processed and analyzed to determine a proper diagnosis. Roughly 50% of patients with a Mendelian genetic disorder are diagnosed using NGS, but a fair number of patients still suffer a diagnostic odyssey. Due to the inherent diversity of the human population, as more exomes or genomes are sequenced, variants of uncertain significance (VUSs) will increase exponentially. Thus, assigning relevance to a VUS (non-synonymous as well as synonymous) in an undiagnosed patient becomes crucial to assess the proper diagnosis. Multiple algorithms have been used to predict how a specific mutation might affect the protein’s function, but they are far from accurate enough to be conclusive. In this work, we highlight the difficulties of genomic variability determined by NGS that have arisen in diagnosing rare genetic diseases, and how molecular modelling has to be a key component to elucidate the relevance of a specific mutation in the protein’s loss of function or malfunction. We suggest that the creation of a multi-omics data model should improve the classification of pathogenicity for a significant amount of the detected genomic variability. Moreover, we argue how it should be incorporated systematically in the process of variant evaluation to be useful in the clinical setting and the diagnostic pipeline.
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Affiliation(s)
- Guerau Fernandez
- Department of Genetic and Molecular Medicine—IPER, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (G.F.); (F.P.); (J.A.)
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, 08950 Barcelona, Spain
| | - Dèlia Yubero
- Department of Genetic and Molecular Medicine—IPER, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (G.F.); (F.P.); (J.A.)
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, 08950 Barcelona, Spain
- Correspondence: ; Tel.: +34-93-600-9451; Fax: +34-93-600-9760
| | - Francesc Palau
- Department of Genetic and Molecular Medicine—IPER, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (G.F.); (F.P.); (J.A.)
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, 08950 Barcelona, Spain
- Division of Pediatrics, University of Barcelona School of Medicine and Health Sciences, 08007 Barcelona, Spain
| | - Judith Armstrong
- Department of Genetic and Molecular Medicine—IPER, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain; (G.F.); (F.P.); (J.A.)
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, 08950 Barcelona, Spain
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