The path toward genomic medicine
The human genome project, via an innumerable series of applications of omics sciences on global health, has led important implications in rare diseases (RDs) [
1]. Among these, the Online Mendelian Inheritance in Man (OMIM,
https://omim.org), is now a free repository which lists all known mendelian genes in which pathogenic variations cause RDs [
2]. Besides, several RD registries and datasets are available worldwide providing huge data sets of patient’s phenotypes and genotypes [
3,
4].
This RD intensive research, accompanied by the development of new therapies, prompts for updated newborn screening strategies, to gain early diagnosis by population screening in all neonates in a defined geography. Since the first Guthrie test for phenylketonuria (PKU) in 1961, biochemical NBS for many treatable RDs have become available, although differently adopted by health systems in various countries across the world [
5]. Biochemical tests were further implemented by tandem mass spectrometry (MS/MS) and are currently performed on screening blood spot cards. Metabolic screening had an immense impact on patients by early detection at a relatively low cost and revolutionized the natural history of many RD types. Nevertheless, significant limitations remain. First, metabolic NBS can be adopted only for diseases which have disease-specific analytes; second, it explores phenotypes, implying that genetic diagnosis must be subsequently very often carried out for disease confirmation; and third, conflicting results are not infrequent [
6]. Consequently, only a limited number of RDs are currently identifiable by metabolic NBS and can benefit from this extraordinary screening tool. Several initiatives are ongoing to explore the feasibility of genetic NBS (gNBS) on a large-scale, using different next-generation sequencing (NGS) approaches [
7‐
12]. The international Consortium (ICoNS,
https://www.iconseq.org) was thoughtfully established to enhance collaboration and data sharing among these initiatives.
Broad implementation of gNBS holds tremendous promise, but also raises important ethical questions. As in routine genetic diagnosis, gNBS needs to meet quality standards, such as accuracy (identifying the variant correctly), sensitivity (probability to detect the variations), specificity (ability to not identify the variations in non-carriers) and clinical validity (ability to predict a specific phenotype) [
13].
Different techniques could be adopted, including targeted sequencing (or TS, also defined as ‘on demand’ gene panels), whole exome sequencing (WES), or whole genome sequencing (WGS). While TS is validated and widely used in diagnostics, WGS might start to gradually replace TS, as soon as WGS can fulfil the standards mentioned above, in addition to possibly becoming more cost effective than TS [
14‐
16].
gNBS must be able to identify all mutation types, including copy number variations (CNVs), to confer full accuracy to the testing; robust data pipelines for variants' calling prioritization and validation are needed, and gNBS for not deferrable RDs (eligible for interventions or therapy in a certain, not flexible, temporal window) needs appropriate reporting turnaround time. All these issues encourage the use of large and high-throughput platforms able to process thousands of samples to secure timely access to care.
Irrespective of the techniques we may prefer to adopt for gNBS, selecting genes/diseases to be screened and how and to whom reports shall be communicated is a crucial task. Following the EURORDIS document listing the 11 key principles to be considered for NBS (
https://www.eurordis.org/publications/key-principles-for-newborn-screening), we need to "decrypt” the definitions of treatable and actionable conditions, before finding rigorous rules for their inclusion in gNBS. The next critical step is reaching some level of consensus on how to build robust genes/diseases selection criteria. An arbitrary disease selection based on technique popularity or availability, or on subjective preference from any stakeholder, not evidenced based, will be unsuccessful. In addition, the RD advocacy community will need to provide evidence that proposed gNBS programs meet the needs of patients. It will be crucial finding a consensus about minimal requirements needed for gNBS adoption in health systems, depending on geographies, cultures, preferences, and means. Related to this last point, the large genetic datasets generated in diverse ethnicities will provide unique information about population-specific clinical utility of gNBS for certain diseases, fact that will possibly address the more appropriate methods to be used. Finally, if gNBS will be adopted by health systems, an unprecedented amount of data will be generated, raising outstanding issues related to data privacy, ethics, and ownership, and how to make optimal and appropriate use of them both in research and healthcare contexts [
17].
Acknowledgements
We acknowledge all the S4C partnership which is visible at the S4C website.
*Screen4Care Consortium members. Joanne Berghout, Pfizer Inc., Collegeville, 19426 PA, USA. Aldona Zygmunt, Pfizer Inc., Collegeville, 19426 PA, USA. Deependra Singh, Pfizer Inc., Collegeville, 19426 PA, USA. Kui A. Huang, Pfizer Inc., Collegeville, 19426 PA, USA. Waltraud Kantz, Pfizer Inc., Collegeville, 19426 PA, USA. Carl Rudolf Blankart, KPM Center for Public Management and Swiss Institute for Translational and Entrepreneurial Medicine, University of Bern, Switzerland. Sandra Gillner, KPM Center for Public Management and Swiss Institute for Translational and Entrepreneurial Medicine, University of Bern, Switzerland. Jiawei Zhao, Department for Mathematics and Computer Science, University of Southern Denmark, Denmark. Richard Roettger Department for Mathematics and Computer Science, University of Southern Denmark, Denmark. Christina Saier, Department of Neuropediatrics and Muscle Disorders, Medical Center, University of Freiburg, Germany. Jan Kirschner Department of Neuropediatrics and Muscle Disorders, Medical Center, University of Freiburg, Germany. Joern Schenk, Takeda Pharmaceuticals International AG, Switzerland. Leon Atkins, Takeda Pharmaceuticals International AG, Switzerland. Nuala Ryan, Takeda Pharmaceuticals International AG, Switzerland. Kaja Zarakowska, Takeda Pharmaceuticals International AG, Switzerland. Jana Zschüntzsch, Universitaetsmedizin Goettingen—Georg-August-Universitaet Goettingen—Stiftung Oeffentlichen Rechts, Germany. Michela Zuccolo, F. Hoffmann La-Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland. Matthias Müllenborn, Novo Nordisk Health Care AG, Switzerland. Yuen-Sum Man, Novo Nordisk Health Care AG, Switzerland. Liz Goodman, University College Dublin, National University of Ireland, Ireland. Marie Trad Lysogene, Neuilly-sur-Seine, France. Anne Sophie Chalandon, Sanofi, Diegem, Belgium. Stefaan Sansen, Sanofi, Diegem, Belgium. Maria Martinez-Fresno, Illumina, UK Shirlene Badger, Illumina, UK. Rudolf Walther van Olden, Novartis Gene Therapies Switzerland GmbH. Robert Rothmann, Ludwig Boltzmann Gesellschaft GmbH Research Institute AG & Co KG, Digital Human Rights Center, Wollzeile 1/1/, Wien. Patrick Lehner, Ludwig Boltzmann Gesellschaft GmbH Research Institute AG & Co KG, Digital Human Rights Center, Wollzeile 1/1/, Wien. Christof Tschohl, Ludwig Boltzmann Gesellschaft GmbH Research Institute AG & Co KG, Digital Human Rights Center, Wollzeile 1/1/, Wien. Ludovic Baillon, PTC Therapeutics Switzerland GmbH, 6312 Steinhausen Schweiz . Gulcin Gumus, EURORDIS, France. Rumen Stefanov, Department of Social Medicine and Public Health, Faculty of Public Health, Medical University of Plovdiv, Plovdiv, Bulgaria. Georgi Iskrov, Department of Social Medicine and Public Health, Faculty of Public Health, Medical University of Plovdiv, Plovdiv, Bulgaria. Ralitsa Raycheva, Department of Social Medicine and Public Health, Faculty of Public Health, Medical University of Plovdiv, Plovdiv, Bulgaria. Kostadin Kostadinov, Department of Social Medicine and Public Health, Faculty of Public Health, Medical University of Plovdiv, Plovdiv, Bulgari Georgi Stefanov, Department of Social Medicine and Public Health, Faculty of Public Health, Medical University of Plovdiv, Plovdiv, Bulgaria. Elena Mitova, Department of Social Medicine and Public Health, Faculty of Public Health, Medical University of Plovdiv, Plovdiv, Bulgaria. Moshe Einhorn, Genoox (Tel Aviv, Israel). Yaron Einhorn, Genoox (Tel Aviv, Israel). Josef Schepers, Charité – Universitätsmedizin Berlin, Berlin Institute of Health. Miriam Hübner, Charité – Universitätsmedizin Berlin, Berlin Institute of Health. Frauke Alves, Translational Molecular Imaging, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany. Rowan Iskandar, Center of Excellence in Decision-Analytic Modeling and Health Economics Research (sitem-insel) AG, Bern, Switzerland. Rudolf Mayer, SBA Research gGmbH, Wien, Austria. Alessandra Renieri, Medical Genetics, University of Siena, Italy. Aneta Piperkova, Personalized Medicine; Digital Health; Patient Advocate, Bulgaria. Ivo Gut, Centro Nacional de Analisis Genomico, CNAG-CRG, Center for Genomic Regulation. Barcelona, Spain. Sergi Beltran, Centro Nacional de Analisis Genomico, CNAG-CRG, Center for Genomic Regulation. Barcelona, Spain. Mads Emil Matthiesen, FindZebra APS, DK. Marion Poetz, Department of strategy and innovation, Copenhagen Business School, DK. Mats Hansson, Uppsala University, Sweden. Regina Trollmann, University of Erlangen, Germany. Emanuele Agolini, Ospedale Pediatrico Bambino Gesu’, IRCCS, Rome, Italy. Silvia Ottombrino, Ospedale Pediatrico Bambino Gesu’, IRCCS, Rome, Italy. Antonio Novelli, Ospedale Pediatrico Bambino Gesu’, IRCCS, Rome, Italy. Enrico Bertini, Ospedale Pediatrico Bambino Gesu’, IRCCS, Rome, Italy. Rita Selvatici, Unit of Medical Genetics, Department of Medical Sciences, University of Ferrara . Marianna Farnè, Unit of Medical Genetics, Department of Medical Sciences, University of Ferrara. Fernanda Fortunato, Unit of Medical Genetics, Department of Medical Sciences, University of Ferrara