title: Pitfalls in genetic testing: the story of missed SCN1A mutations.
abstract: BACKGROUND
  Sanger sequencing, still the standard technique for genetic testing in most diagnostic laboratories and until recently widely used in research, is gradually being complemented by next-generation sequencing (NGS). No single mutation detection technique is however perfect in identifying all mutations. Therefore, we wondered to what extent inconsistencies between Sanger sequencing and NGS affect the molecular diagnosis of patients. Since mutations in SCN1A, the major gene implicated in epilepsy, are found in the majority of Dravet syndrome (DS) patients, we focused on missed SCN1A mutations.
  
  
  METHODS
  We sent out a survey to 16 genetic centers performing SCN1A testing.
  
  
  RESULTS
  We collected data on 28 mutations initially missed using Sanger sequencing. All patients were falsely reported as SCN1A mutation-negative, both due to technical limitations and human errors.
  
  
  CONCLUSIONS
  We illustrate the pitfalls of Sanger sequencing and most importantly provide evidence that SCN1A mutations are an even more frequent cause of DS than already anticipated.
authors.affiliation: Neurogenetics groupDepartment of Molecular GeneticsVIBAntwerpBelgium; Laboratory of NeurogeneticsInstitute Born-BungeUniversity of AntwerpAntwerpBelgium.
authors.forename: Tania
authors.initials: T
authors.lastname: Djémié
authors.affiliation: Neurogenetics groupDepartment of Molecular GeneticsVIBAntwerpBelgium; Laboratory of NeurogeneticsInstitute Born-BungeUniversity of AntwerpAntwerpBelgium; Sorbonne universitésUPMC université Paris 0691-105boulevard de l'HôpitalParis75013France; ICM, CNRS UMR 7225, Inserm U 112747/83, boulevard de l'HôpitalParis75013France; Centre de reference épilepsies raresEpilepsy unit, AP-HP Groupe hospitalier Pitié-SalpêtrièreParis75013France.
authors.forename: Sarah
authors.initials: S
authors.lastname: Weckhuysen
authors.affiliation: Department of Neuropediatrics University Medical Center Schleswig-Holstein Kiel Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: von Spiczak
authors.affiliation: Division of Genetic Medicine Department of Pediatrics University of Washington Seattle Washington 98195 USA.
authors.forename: Gemma L
authors.initials: GL
authors.lastname: Carvill
authors.affiliation: Department of Neuropediatrics University Medical Center Schleswig-Holstein Kiel Germany.
authors.forename: Johanna
authors.initials: J
authors.lastname: Jaehn
authors.affiliation: Folkhälsan Institute of GeneticsHelsinkiFinland; Medical and Clinical GeneticsUniversity of HelsinkiHelsinkiFinland; Helsinki University HospitalHelsinkiFinland.
authors.forename: Anna-Kaisa
authors.initials: AK
authors.lastname: Anttonen
authors.affiliation: Department of Medical Genetics University Medical Center Utrecht Utrecht The Netherlands.
authors.forename: Eva
authors.initials: E
authors.lastname: Brilstra
authors.affiliation: Department of Molecular Biology and Genetics Bogaziçi University Istanbul Turkey.
authors.forename: Hande S
authors.initials: HS
authors.lastname: Caglayan
authors.affiliation: Department of Medical Genetics University Medical Center Utrecht Utrecht The Netherlands.
authors.forename: Carolien G
authors.initials: CG
authors.lastname: de Kovel
authors.affiliation: Sorbonne universitésUPMC université Paris 0691-105boulevard de l'HôpitalParis75013France; ICM, CNRS UMR 7225, Inserm U 112747/83, boulevard de l'HôpitalParis75013France; Département de génétiqueAP-HP, hôpital Pitié-Salpêtrière47/83boulevard de l'HôpitalParis75013France.
authors.forename: Christel
authors.initials: C
authors.lastname: Depienne
authors.affiliation: Department of Pediatric Neurology Helsinki University Hospital Helsinki Finland.
authors.forename: Eija
authors.initials: E
authors.lastname: Gaily
authors.affiliation: Laboratory of Genetics E.O. Ospedali Galliera Genova Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Gennaro
authors.affiliation: Neurology Laboratory and Epilepsy UnitDepartment of NeurologyInstituto de Investigatión Sanitaria-Fundación Jiménez Díaz, Universidad Autónoma de MadridMadridSpain; IIS-Fundación Jiménez Díaz and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER)MadridSpain.
authors.forename: Beatriz G
authors.initials: BG
authors.lastname: Giraldez
authors.affiliation: Psychiatric and Neurodevelopmental Genetics UnitMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusetts02114USA; Program in Medical and Population GeneticsBroad Institute of MIT and HarvardCambridgeMassachusetts02142USA; Stanley Center for Psychiatric ResearchBroad Institute of MIT and HarvardCambridgeMassachusetts02142USA; Wellcome Trust Sanger InstituteHinxtonUnited Kingdom.
authors.forename: Padhraig
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authors.lastname: Gormley
authors.affiliation: IIS-Fundación Jiménez Díaz and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) Madrid Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: Guerrero-López
authors.affiliation: Pediatric Neurology and Neurogenetics Unit and Laboratories A. Meyer Children's Hospital-University of Florence Florence Italy.
authors.forename: Renzo
authors.initials: R
authors.lastname: Guerrini
authors.affiliation: Wellcome Trust Sanger InstituteHinxtonUnited Kingdom; Institute for Molecular Medicine Finland FIMMUniversity of HelsinkiHelsinkiFinland.
authors.forename: Eija
authors.initials: E
authors.lastname: Hämäläinen
authors.affiliation: Department of Neuropediatrics University Medical Center Schleswig-Holstein Kiel Germany.
authors.forename: Corinna
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authors.lastname: Hartmann
authors.affiliation: Department of Clinical and Experimental EpilepsyNIHR University College London Hospitals Biomedical Research CentreUCL Institute of NeurologyLondonUnited Kingdom; The Epilepsy SocietyChalfont-St-PeterBucksUnited Kingdom.
authors.forename: Laura
authors.initials: L
authors.lastname: Hernandez-Hernandez
authors.affiliation: Department of NeurologyDanish Epilepsy CentreDianalundDenmark; Institute for Regional Health researchUniversity of Southern DenmarkOdenseDenmark.
authors.forename: Helle
authors.initials: H
authors.lastname: Hjalgrim
authors.affiliation: Department of Medical Genetics University Medical Center Utrecht Utrecht The Netherlands.
authors.forename: Bobby P C
authors.initials: BP
authors.lastname: Koeleman
authors.affiliation: Sorbonne universitésUPMC université Paris 0691-105boulevard de l'HôpitalParis75013France; ICM, CNRS UMR 7225, Inserm U 112747/83, boulevard de l'HôpitalParis75013France; Département de génétiqueAP-HP, hôpital Pitié-Salpêtrière47/83boulevard de l'HôpitalParis75013France.
authors.forename: Eric
authors.initials: E
authors.lastname: Leguern
authors.affiliation: Folkhälsan Institute of GeneticsHelsinkiFinland; Research Programs UnitMolecular NeurologyUniversity of HelsinkiHelsinkiFinland.
authors.forename: Anna-Elina
authors.initials: AE
authors.lastname: Lehesjoki
authors.affiliation: Institute of Human Genetics University of Leipzig Leipzig Germany.
authors.forename: Johannes R
authors.initials: JR
authors.lastname: Lemke
authors.affiliation: Department of Clinical and Experimental Epilepsy NIHR University College London Hospitals Biomedical Research Centre UCL Institute of Neurology London United Kingdom.
authors.forename: Costin
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authors.lastname: Leu
authors.affiliation: Pediatric Neurology and Neurogenetics Unit and Laboratories A. Meyer Children's Hospital-University of Florence Florence Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Marini
authors.affiliation: Epilepsy Research Centre Department of Medicine University of Melbourne Austin Health Melbourne Australia.
authors.forename: Jacinta M
authors.initials: JM
authors.lastname: McMahon
authors.affiliation: Pediatric Neurology and Neurogenetics Unit and Laboratories A. Meyer Children's Hospital-University of Florence Florence Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Mei
authors.affiliation: Department of NeurologyDanish Epilepsy CentreDianalundDenmark; Institute for Regional Health researchUniversity of Southern DenmarkOdenseDenmark.
authors.forename: Rikke S
authors.initials: RS
authors.lastname: Møller
authors.affiliation: Department of Neuropediatrics University Medical Center Schleswig-Holstein Kiel Germany.
authors.forename: Hiltrud
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authors.lastname: Muhle
authors.affiliation: Division of Genetic Medicine Department of Pediatrics University of Washington Seattle Washington 98195 USA.
authors.forename: Candace T
authors.initials: CT
authors.lastname: Myers
authors.affiliation: Sorbonne universitésUPMC université Paris 0691-105boulevard de l'HôpitalParis75013France; ICM, CNRS UMR 7225, Inserm U 112747/83, boulevard de l'HôpitalParis75013France; Département de génétiqueAP-HP, hôpital Pitié-Salpêtrière47/83boulevard de l'HôpitalParis75013France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Nava
authors.affiliation: Neurology Laboratory and Epilepsy UnitDepartment of NeurologyInstituto de Investigatión Sanitaria-Fundación Jiménez Díaz, Universidad Autónoma de MadridMadridSpain; IIS-Fundación Jiménez Díaz and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER)MadridSpain.
authors.forename: Jose M
authors.initials: JM
authors.lastname: Serratosa
authors.affiliation: Department of Clinical and Experimental EpilepsyNIHR University College London Hospitals Biomedical Research CentreUCL Institute of NeurologyLondonUnited Kingdom; The Epilepsy SocietyChalfont-St-PeterBucksUnited Kingdom.
authors.forename: Sanjay M
authors.initials: SM
authors.lastname: Sisodiya
authors.affiliation: Department of Neuropediatrics University Medical Center Schleswig-Holstein Kiel Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Stephani
authors.affiliation: Pediatric Neurology and Muscular Diseases Unit Department of Neurosciences Rehabilitation Ophthalmology Genetics and Maternal and Child Health University of Genoa 'G. Gaslini' Institute Genova Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Striano
authors.affiliation: Department of Medical Genetics University Medical Center Utrecht Utrecht The Netherlands.
authors.forename: Marjan J A
authors.initials: MJ
authors.lastname: van Kempen
authors.affiliation: Department of Medical Genetics University Medical Center Utrecht Utrecht The Netherlands.
authors.forename: Nienke E
authors.initials: NE
authors.lastname: Verbeek
authors.affiliation: Department of Molecular Biology and Genetics Bogaziçi University Istanbul Turkey.
authors.forename: Sunay
authors.initials: S
authors.lastname: Usluer
authors.affiliation: Laboratory of Neurogenetics Department of Neurosciences Giannina Gaslini Institute Genova Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Zara
authors.affiliation: Program in Medical and Population GeneticsBroad Institute of MIT and HarvardCambridgeMassachusetts02142USA; Institute for Molecular Medicine Finland FIMMUniversity of HelsinkiHelsinkiFinland.
authors.forename: Aarno
authors.initials: A
authors.lastname: Palotie
authors.affiliation: Division of Genetic Medicine Department of Pediatrics University of Washington Seattle Washington 98195 USA.
authors.forename: Heather C
authors.initials: HC
authors.lastname: Mefford
authors.affiliation: Epilepsy Research CentreDepartment of MedicineUniversity of MelbourneAustin HealthMelbourneAustralia; Department of PaediatricsUniversity of Melbourne and Royal Children's HospitalParkvilleVictoria3052Australia; Florey Institute of Neuroscience and Mental HealthMelbourneVictoria3084Australia.
authors.forename: Ingrid E
authors.initials: IE
authors.lastname: Scheffer
authors.affiliation: Neurogenetics groupDepartment of Molecular GeneticsVIBAntwerpBelgium; Laboratory of NeurogeneticsInstitute Born-BungeUniversity of AntwerpAntwerpBelgium; Division of NeurologyAntwerp University HospitalAntwerpBelgium.
authors.forename: Peter
authors.initials: P
authors.lastname: De Jonghe
authors.affiliation: Department of NeuropediatricsUniversity Medical Center Schleswig-HolsteinKielGermany; Division of NeurologyChildren's Hospital of PhiladelphiaPhiladelphiaPennsylvaniaUSA.
authors.forename: Ingo
authors.initials: I
authors.lastname: Helbig
authors.affiliation: Neurogenetics groupDepartment of Molecular GeneticsVIBAntwerpBelgium; Laboratory of NeurogeneticsInstitute Born-BungeUniversity of AntwerpAntwerpBelgium; GENOMEDCenter for Medical GeneticsUniversity of AntwerpAntwerpBelgium.
authors.forename: Arvid
authors.initials: A
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keywords: Dravet syndrome; Sanger sequencing; epilepsy; genetic screening; next‐generation sequencing