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Severe myoclonic epilepsy in infancy(DRVT)

MedGen UID:
148243
Concept ID:
C0751122
Disease or Syndrome
Synonyms: DEVELOPMENTAL AND EPILEPTIC ENCEPHALOPATHY 6A; Dravet syndrome; DRVT; Epilepsy, Myoclonic, Infantile, Severe; Epileptic encephalopathy, early infantile, 6 (Dravet syndrome)
SNOMED CT: Severe myoclonic epilepsy in infancy (230437002); Dravet Syndrome (230437002)
Modes of inheritance:
Autosomal dominant inheritance
MedGen UID:
141047
Concept ID:
C0443147
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele.
 
Gene (location): SCN1A (2q24.3)
 
Monarch Initiative: MONDO:0100135
OMIM®: 607208
Orphanet: ORPHA33069

Disease characteristics

Excerpted from the GeneReview: SCN1A Seizure Disorders
SCN1A seizure disorders encompass a spectrum that ranges from simple febrile seizures and generalized epilepsy with febrile seizures plus (GEFS+) at the mild end to Dravet syndrome and intractable childhood epilepsy with generalized tonic-clonic seizures (ICE-GTC) at the severe end. Phenotypes with intractable seizures including Dravet syndrome are often associated with cognitive decline. Less commonly observed phenotypes include myoclonic astatic epilepsy (MAE), Lennox-Gastaut syndrome, infantile spasms, epilepsy with focal seizures, and vaccine-related encephalopathy and seizures. The phenotype of SCN1A seizure disorders can vary even within the same family. [from GeneReviews]
Authors:
Ian O Miller  |  Marcio A Sotero de Menezes   view full author information

Additional description

From OMIM
Dravet syndrome, first described by Dravet (1978), is a clinical term for a severe neurologic disorder characterized by the onset of seizures in the first year of life after normal early development. Affected individuals usually present with generalized tonic, clonic, and tonic-clonic seizures that may initially be induced by fever and are usually refractory to treatment. Later, patients tend to manifest other seizure types, including absence, myoclonic, and partial seizures. The EEG is often normal at first, but later characteristically shows generalized spike-wave activity and other abnormalities. Psychomotor development stagnates around the second year of life, and affected individuals show subsequent mental decline, behavioral problems, and learning disabilities (summary by Dravet et al., 1992; Sugawara et al., 2002; Harkin et al., 2007; Shbarou and Mikati, 2016). 'Severe myoclonic epilepsy of infancy' (SMEI) and 'migrating partial seizures of infancy' (MPSI) are other clinical manifestations of Dravet syndrome (summary by Ohmori et al., 2002; Carranza Rojo et al., 2011; Dravet et al., 2011). Although most cases of Dravet syndrome are caused by mutation in the SCN1A gene, there are other developmental and epileptic encephalopathies (DEEs) with clinical features similar to Dravet syndrome that are caused by mutations in other genes (summary by Steel et al., 2017). For a discussion of genetic heterogeneity of DEE, see 308350.  http://www.omim.org/entry/607208

Clinical features

From HPO
Cerebellar ataxia
MedGen UID:
849
Concept ID:
C0007758
Disease or Syndrome
Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly).
Intellectual disability, moderate
MedGen UID:
7680
Concept ID:
C0026351
Mental or Behavioral Dysfunction
Moderate mental retardation is defined as an intelligence quotient (IQ) in the range of 35-49.
Intellectual disability, severe
MedGen UID:
48638
Concept ID:
C0036857
Mental or Behavioral Dysfunction
Severe mental retardation is defined as an intelligence quotient (IQ) in the range of 20-34.
Status epilepticus
MedGen UID:
11586
Concept ID:
C0038220
Disease or Syndrome
Status epilepticus is a type of prolonged seizure resulting either from the failure of the mechanisms responsible for seizure termination or from the initiation of mechanisms which lead to abnormally prolonged seizures (after time point t1). It is a condition that can have long-term consequences (after time point t2), including neuronal death, neuronal injury, and alteration of neuronal networks, depending on the type and duration of seizures.
Abnormal pyramidal sign
MedGen UID:
68582
Concept ID:
C0234132
Sign or Symptom
Functional neurological abnormalities related to dysfunction of the pyramidal tract.
Focal aware seizure
MedGen UID:
65895
Concept ID:
C0234974
Disease or Syndrome
A type of focal-onset seizure in which awareness is preserved. Awareness during a seizure is defined as the patient being fully aware of themself and their environment throughout the seizure, even if immobile.
Mental deterioration
MedGen UID:
66713
Concept ID:
C0234985
Mental or Behavioral Dysfunction
Loss of previously present mental abilities, generally in adults.
Cerebral atrophy
MedGen UID:
116012
Concept ID:
C0235946
Disease or Syndrome
Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.
Focal impaired awareness seizure
MedGen UID:
543022
Concept ID:
C0270834
Disease or Syndrome
Focal impaired awareness seizure (or focal seizure with impaired or lost awareness) is a type of focal-onset seizure characterized by some degree (which may be partial) of impairment of the person's awareness of themselves or their surroundings at any point during the seizure.
Atonic seizure
MedGen UID:
78735
Concept ID:
C0270846
Disease or Syndrome
Atonic seizure is a type of motor seizure characterized by a sudden loss or diminution of muscle tone without apparent preceding myoclonic or tonic event lasting about 1 to 2 seconds, involving head, trunk, jaw, or limb musculature.
Bilateral tonic-clonic seizure
MedGen UID:
141670
Concept ID:
C0494475
Sign or Symptom
A bilateral tonic-clonic seizure is a seizure defined by a tonic (bilateral increased tone, lasting seconds to minutes) and then a clonic (bilateral sustained rhythmic jerking) phase.
Epileptic encephalopathy
MedGen UID:
452596
Concept ID:
C0543888
Disease or Syndrome
A condition in which epileptiform abnormalities are believed to contribute to the progressive disturbance in cerebral function. Epileptic encephalaopathy is characterized by (1) electrographic EEG paroxysmal activity that is often aggressive, (2) seizures that are usually multiform and intractable, (3) cognitive, behavioral and neurological deficits that may be relentless, and (4) sometimes early death.
Global developmental delay
MedGen UID:
107838
Concept ID:
C0557874
Finding
A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
Developmental regression
MedGen UID:
324613
Concept ID:
C1836830
Disease or Syndrome
Loss of developmental skills, as manifested by loss of developmental milestones.
Focal hemiclonic seizure
MedGen UID:
335477
Concept ID:
C1846620
Disease or Syndrome
A type of focal clonic seizure characterized by sustained rhythmic jerking rapidly involves one side of the body at seizure onset.
Motor delay
MedGen UID:
381392
Concept ID:
C1854301
Finding
A type of Developmental delay characterized by a delay in acquiring motor skills.
Visually-induced seizure
MedGen UID:
1720648
Concept ID:
C2080645
Disease or Syndrome
Seizures evoked by visual stimuli. This includes clinical seizures induced by strobe lighting, television and other screens, flickering environmental lighting and self-induction by causing a strobe effect.
Generalized myoclonic seizure
MedGen UID:
892704
Concept ID:
C4021759
Disease or Syndrome
A generalized myoclonic seizure is a type of generalized motor seizure characterised by bilateral, sudden, brief (<100 ms) involuntary single or multiple contraction of muscles or muscle groups of variable topography (axial, proximal limb, distal). Myoclonus is less regularly repetitive and less sustained than is clonus.
Generalized clonic seizure
MedGen UID:
869081
Concept ID:
C4023499
Disease or Syndrome
Generalized clonic seizure is a type of generalized motor seizure characterised by sustained bilateral jerking, either symmetric or asymmetric, that is regularly repetitive and involves the same muscle groups.
Generalized non-motor (absence) seizure
MedGen UID:
1385688
Concept ID:
C4316903
Disease or Syndrome
A generalized non-motor (absence) seizure is a type of a type of dialeptic seizure that is of electrographically generalized onset. It is a generalized seizure characterised by an interruption of activities, a blank stare, and usually the person will be unresponsive when spoken to. Any ictal motor phenomena are minor in comparison to these non-motor features.
Myoclonic seizure
MedGen UID:
1385980
Concept ID:
C4317123
Sign or Symptom
A myoclonic seizure is a type of motor seizure characterised by sudden, brief (<100 ms) involuntary single or multiple contraction of muscles or muscle groups of variable topography (axial, proximal limb, distal). Myoclonus is less regularly repetitive and less sustained than is clonus.
Secondary microcephaly
MedGen UID:
608952
Concept ID:
C0431352
Finding
Head circumference which falls below 2 standard deviations below the mean for age and gender because of insufficient head growth after birth.
Cerebral visual impairment
MedGen UID:
890568
Concept ID:
C4048268
Pathologic Function
A form of loss of vision caused by damage to the visual cortex rather than a defect in the eye.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVSevere myoclonic epilepsy in infancy

Professional guidelines

PubMed

Miziak B, Czuczwar S
Expert Opin Drug Discov 2021 May;16(5):579-593. Epub 2020 Dec 17 doi: 10.1080/17460441.2021.1857722. PMID: 33275464
Brigo F, Storti M
Cochrane Database Syst Rev 2013 Nov 19;(11):CD010483. doi: 10.1002/14651858.CD010483.pub2. PMID: 24254932
Ceulemans B
Dev Med Child Neurol 2011 Apr;53 Suppl 2:19-23. doi: 10.1111/j.1469-8749.2011.03968.x. PMID: 21504428

Curated

Orphanet, Dravet syndrome, 2008

Suggested Reading

PubMed

Steel D, Symonds JD, Zuberi SM, Brunklaus A
Epilepsia 2017 Nov;58(11):1807-1816. Epub 2017 Sep 7 doi: 10.1111/epi.13889. PMID: 28880996

Recent clinical studies

Etiology

Pavone P, Corsello G, Ruggieri M, Marino S, Marino S, Falsaperla R
Ital J Pediatr 2018 May 15;44(1):54. doi: 10.1186/s13052-018-0491-z. PMID: 29764460Free PMC Article
Brigo F, Storti M
Cochrane Database Syst Rev 2013 Nov 19;(11):CD010483. doi: 10.1002/14651858.CD010483.pub2. PMID: 24254932
Kassaï B, Chiron C, Augier S, Cucherat M, Rey E, Gueyffier F, Guerrini R, Vincent J, Dulac O, Pons G
Epilepsia 2008 Feb;49(2):343-8. Epub 2007 Nov 19 doi: 10.1111/j.1528-1167.2007.01423.x. PMID: 18028411
Chiron C
Expert Opin Investig Drugs 2005 Jul;14(7):905-11. doi: 10.1517/13543784.14.7.905. PMID: 16022579
Baulac S, Gourfinkel-An I, Nabbout R, Huberfeld G, Serratosa J, Leguern E, Baulac M
Lancet Neurol 2004 Jul;3(7):421-30. doi: 10.1016/S1474-4422(04)00808-7. PMID: 15207799

Diagnosis

Pavone P, Corsello G, Ruggieri M, Marino S, Marino S, Falsaperla R
Ital J Pediatr 2018 May 15;44(1):54. doi: 10.1186/s13052-018-0491-z. PMID: 29764460Free PMC Article
Dravet C, Oguni H
Handb Clin Neurol 2013;111:627-33. doi: 10.1016/B978-0-444-52891-9.00065-8. PMID: 23622210
Dravet C
Epilepsia 2011 Apr;52 Suppl 2:3-9. doi: 10.1111/j.1528-1167.2011.02994.x. PMID: 21463272
Kassaï B, Chiron C, Augier S, Cucherat M, Rey E, Gueyffier F, Guerrini R, Vincent J, Dulac O, Pons G
Epilepsia 2008 Feb;49(2):343-8. Epub 2007 Nov 19 doi: 10.1111/j.1528-1167.2007.01423.x. PMID: 18028411
Dulac O
Epilepsia 2001;42 Suppl 3:23-6. doi: 10.1046/j.1528-1157.2001.042suppl.3023.x. PMID: 11520318

Therapy

Brigo F, Storti M
Cochrane Database Syst Rev 2013 Nov 19;(11):CD010483. doi: 10.1002/14651858.CD010483.pub2. PMID: 24254932
Kassaï B, Chiron C, Augier S, Cucherat M, Rey E, Gueyffier F, Guerrini R, Vincent J, Dulac O, Pons G
Epilepsia 2008 Feb;49(2):343-8. Epub 2007 Nov 19 doi: 10.1111/j.1528-1167.2007.01423.x. PMID: 18028411
Chiron C
Neurotherapeutics 2007 Jan;4(1):123-5. doi: 10.1016/j.nurt.2006.10.001. PMID: 17199026Free PMC Article
Chiron C
Expert Opin Investig Drugs 2005 Jul;14(7):905-11. doi: 10.1517/13543784.14.7.905. PMID: 16022579
Dulac O
Epilepsia 2001;42 Suppl 3:23-6. doi: 10.1046/j.1528-1157.2001.042suppl.3023.x. PMID: 11520318

Prognosis

Pavone P, Corsello G, Ruggieri M, Marino S, Marino S, Falsaperla R
Ital J Pediatr 2018 May 15;44(1):54. doi: 10.1186/s13052-018-0491-z. PMID: 29764460Free PMC Article
Shbarou R, Mikati MA
Semin Pediatr Neurol 2016 May;23(2):134-42. Epub 2016 Jun 2 doi: 10.1016/j.spen.2016.06.002. PMID: 27544470
Akiyama M, Kobayashi K, Ohtsuka Y
Acta Med Okayama 2012;66(5):369-76. doi: 10.18926/AMO/48961. PMID: 23093055
Dravet C
Epilepsia 2011 Apr;52 Suppl 2:3-9. doi: 10.1111/j.1528-1167.2011.02994.x. PMID: 21463272
Kassaï B, Chiron C, Augier S, Cucherat M, Rey E, Gueyffier F, Guerrini R, Vincent J, Dulac O, Pons G
Epilepsia 2008 Feb;49(2):343-8. Epub 2007 Nov 19 doi: 10.1111/j.1528-1167.2007.01423.x. PMID: 18028411

Clinical prediction guides

Bertuccelli M, Verheyen K, Hallemans A, Sander JW, Ragona F, Bisiacchi P, Masiero S, Del Felice A
Epilepsia 2021 Apr;62(4):874-887. Epub 2021 Mar 1 doi: 10.1111/epi.16844. PMID: 33646591
Dravet C
Epilepsia 2011 Apr;52 Suppl 2:3-9. doi: 10.1111/j.1528-1167.2011.02994.x. PMID: 21463272
Gambardella A, Marini C
Epilepsia 2009 May;50 Suppl 5:20-3. doi: 10.1111/j.1528-1167.2009.02115.x. PMID: 19469841
Yamakawa K
Brain Dev 2009 May;31(5):401-4. Epub 2009 Feb 8 doi: 10.1016/j.braindev.2008.11.015. PMID: 19203854
Baulac S, Gourfinkel-An I, Nabbout R, Huberfeld G, Serratosa J, Leguern E, Baulac M
Lancet Neurol 2004 Jul;3(7):421-30. doi: 10.1016/S1474-4422(04)00808-7. PMID: 15207799

Recent systematic reviews

Rampazzo ACM, Dos Santos RRP, Maluf FA, Simm RF, Marson FAL, Ortega MM, de Aguiar PHP
Neurogenetics 2021 May;22(2):105-115. Epub 2021 May 3 doi: 10.1007/s10048-021-00644-7. PMID: 33937968
Bertuccelli M, Verheyen K, Hallemans A, Sander JW, Ragona F, Bisiacchi P, Masiero S, Del Felice A
Epilepsia 2021 Apr;62(4):874-887. Epub 2021 Mar 1 doi: 10.1111/epi.16844. PMID: 33646591
Brigo F, Storti M
Cochrane Database Syst Rev 2013 Nov 19;(11):CD010483. doi: 10.1002/14651858.CD010483.pub2. PMID: 24254932
Kassaï B, Chiron C, Augier S, Cucherat M, Rey E, Gueyffier F, Guerrini R, Vincent J, Dulac O, Pons G
Epilepsia 2008 Feb;49(2):343-8. Epub 2007 Nov 19 doi: 10.1111/j.1528-1167.2007.01423.x. PMID: 18028411

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