August 09, 2017ArticleOpen Access
Not all SCN1A epileptic encephalopathies are Dravet syndrome
Early profound Thr226Met phenotype
Lynette G. Sadleir, Emily I. Mountier, Deepak Gill, Suzanne Davis, Charuta Joshi, Catherine DeVile, Manju A. Kurian, For the DDD Study, Simone Mandelstam, Elaine Wirrell, Katherine C. Nickels, Hema R. Murali, Gemma Carvill, Candace T. Myers, Heather C. Mefford and Ingrid E. Scheffer
First published August 9, 2017, DOI: https://doi.org/10.1212/WNL.0000000000004331
Lynette G. Sadleir
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Emily I. Mountier
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Deepak Gill
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Suzanne Davis
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Charuta Joshi
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Catherine DeVile
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Manju A. Kurian
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Simone Mandelstam
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Elaine Wirrell
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Katherine C. Nickels
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Hema R. Murali
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Gemma Carvill
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Candace T. Myers
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Heather C. Mefford
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Ingrid E. Scheffer
From the Department of Paediatrics and Child Health (L.G.S., E.I.M.), University of Otago, Wellington, New Zealand; Department of Neurology (D.G.), University of Sydney, Australia; Department of Neurology (S.D.), Starship Children's Health, Auckland, New Zealand; Department of Neurology (C.J.), Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Denver; Department of Neurology (C.D.V., M.A.K.), Great Ormond Street Hospital for Children; Developmental Neurosciences (M.A.K.), UCL Great Ormond Street Institute of Child Health, London; Wellcome Trust Sanger Institute (DDD Study Group), Hinxton, Cambridge, UK; Departments of Paediatrics and Radiology (S.M.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (S.M., I.E.S.); Department of Medical Imaging (S.M.), Royal Children's Hospital, Melbourne, Australia; Department of Neurology (E.W., K.C.N.), Mayo Clinic, Rochester, MN; Department of Neurology (H.R.M.), Marshfield Clinic, WI; Division of Genetic Medicine (G.C., C.T.M., H.C.M.), Department of Pediatrics, University of Washington, Seattle; and Departments of Medicine and Paediatrics (I.E.S.), University of Melbourne, Austin Health and Royal Children's Hospital, Australia.
Not all SCN1A epileptic encephalopathies are Dravet syndrome
Lynette G. Sadleir, Emily I. Mountier, Deepak Gill, Suzanne Davis, Charuta Joshi, Catherine DeVile, Manju A. Kurian, For the DDD Study, Simone Mandelstam, Elaine Wirrell, Katherine C. Nickels, Hema R. Murali, Gemma Carvill, Candace T. Myers, Heather C. Mefford, Ingrid E. Scheffer
Neurology Aug 2017, 10.1212/WNL.0000000000004331; DOI: 10.1212/WNL.0000000000004331
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Abstract
Objective: To define a distinct SCN1A developmental and epileptic encephalopathy with early onset, profound impairment, and movement disorder.
Methods: A case series of 9 children were identified with a profound developmental and epileptic encephalopathy and SCN1A mutation.
Results: We identified 9 children 3 to 12 years of age; 7 were male. Seizure onset was at 6 to 12 weeks with hemiclonic seizures, bilateral tonic-clonic seizures, or spasms. All children had profound developmental impairment and were nonverbal and nonambulatory, and 7 of 9 required a gastrostomy. A hyperkinetic movement disorder occurred in all and was characterized by dystonia and choreoathetosis with prominent oral dyskinesia and onset from 2 to 20 months of age. Eight had a recurrent missense SCN1A mutation, p.Thr226Met. The remaining child had the missense mutation p.Pro1345Ser. The mutation arose de novo in 8 of 9; for the remaining case, the mother was negative and the father was unavailable.
Conclusions: Here, we present a phenotype-genotype correlation for SCN1A. We describe a distinct SCN1A phenotype, early infantile SCN1A encephalopathy, which is readily distinguishable from the well-recognized entities of Dravet syndrome and genetic epilepsy with febrile seizures plus. This disorder has an earlier age at onset, profound developmental impairment, and a distinctive hyperkinetic movement disorder, setting it apart from Dravet syndrome. Remarkably, 8 of 9 children had the recurrent missense mutation p.Thr226Met.
Footnotes
↵* Authors in the DDD Study Group.
- Received January 17, 2017.
- Accepted in final form June 16, 2017.
- Copyright © 2017 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.
This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (CC BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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