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Myoclonic epilepsy, juvenile, susceptibility to, 1(EJM1)

MedGen UID:: 342587
•Concept ID:: C1850778
•: Finding

Synonyms:	EJM1; Myoclonic Epilepsy, Juvenile, 1

Gene (location): Gene(s) directly associated with this condition or phenotype.	EFHC1 (6p12.2)

Monarch Initiative:	MONDO:0020752
OMIM®:	254770

Definition

Juvenile myoclonic epilepsy (EJM, JME) is a subtype of idiopathic generalized epilepsy (EIG; see 600669), affecting up to 26% of all individuals with EIG. Individuals with EJM have afebrile seizures only, with onset in adolescence of myoclonic jerks. Myoclonic jerks usually occur in the morning (Janz and Durner, 1997). Genetic Heterogeneity of Juvenile Myoclonic Seizures Susceptibility to EJM can be conferred by variation in several other genes: EJM5 (611136), by variation in the GABRA1 gene (137160) on 5q34; EJM6 (see 607682), by variation in the CACNB4 gene (601949) on 2q23; EJM8 (see 607628), by variation in the CLCN2 gene (600570) on 3q27; and EJM10 (617924), by variation in the ICK gene (612325) on chromosome 6p12. In addition, EJM loci have been identified by linkage analysis: EJM2 (see 604827) on 15q14, EJM3 (608816) on 6p21, EJM4 (611364) on 5q12-q14, and EJM9 (614280) on 2q33-q36. EJM7 (see 613060) was thought to be caused by variation in the GABRD gene (137163.0002) on 1p36, but the variant was reclassified as a polymorphism. [from OMIM]

Clinical features

From HPO

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.

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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.

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Morning myoclonic jerks

MedGen UID:: 335620
•Concept ID:: C1847164
•: Finding

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Intellectual disability

MedGen UID:: 811461
•Concept ID:: C3714756
•: Mental or Behavioral Dysfunction

Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.

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EEG with generalized polyspikes

MedGen UID:: 868685
•Concept ID:: C4023088
•: Finding

EEG with repetitive generalized sharp transient waves of a duration less than 80 msec.

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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 characterized 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.

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Myoclonic seizure

MedGen UID:: 1385980
•Concept ID:: C4317123
•: Sign or Symptom

A myoclonic seizure is a type of motor seizure characterized 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.

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Abnormality of the nervous system

Term Hierarchy

GTR
MeSH

CClinical test, RResearch test, OOMIM, GGeneReviews, VClinVar

CROGVIdiopathic generalized epilepsy
- CROGVAbsence seizure
- CROGVJuvenile myoclonic epilepsy
  - CROGVEpilepsy, idiopathic generalized, susceptibility to, 7
  - CROGVEpilepsy, idiopathic generalized, susceptibility to, 9
  - CROGVEpilepsy, idiopathic generalized, susceptibility to, 11
  - CROGVEpilepsy, idiopathic generalized, susceptibility to, 13
  - CROGVEpilepsy, juvenile myoclonic 7
  - CROGVEpilepsy, juvenile myoclonic, susceptibility to, 6
  - CROGVEPILEPSY, JUVENILE MYOCLONIC, SUSCEPTIBILITY TO, 8
  - CROGVMyoclonic epilepsy, juvenile, susceptibility to, 1
  - CROGVMyoclonic epilepsy, juvenile, susceptibility to, 3
  - CROGVMyoclonic epilepsy, juvenile, susceptibility to, 4

Disorder by Site
- Disorder of nervous system
  - Disorder of the central nervous system
    - Brain disorder
      - Epilepsy
        Juvenile myoclonic epilepsy
        Myoclonic epilepsy, juvenile, susceptibility to, 1

Professional guidelines

PubMed

Multi-gene panel testing in Korean patients with common genetic generalized epilepsy syndromes.

Lee CG, Lee J, Lee M
PLoS One 2018;13(6):e0199321. Epub 2018 Jun 20 doi: 10.1371/journal.pone.0199321. PMID: 29924869 Free PMC Article

See all (1)

Recent clinical studies

Etiology

Alzheimer Disease and Epilepsy: A Mendelian Randomization Study.

Fang Y, Si X, Wang J, Wang Z, Chen Y, Liu Y, Yan Y, Tian J, Zhang B, Pu J
Neurology 2023 Jul 25;101(4):e399-e409. Epub 2023 May 24 doi: 10.1212/WNL.0000000000207423. PMID: 37225432 Free PMC Article

Childhood Absence Epilepsy evolving to Eyelid Myoclonia with Absence Epilepsy.

Galli J, Micheletti S, Malerba L, Fazzi E, Giordano L
Seizure 2018 Oct;61:1-3. Epub 2018 Jul 18 doi: 10.1016/j.seizure.2018.07.009. PMID: 30029089

DNA methylation of the BRD2 promoter is associated with juvenile myoclonic epilepsy in Caucasians.

Pathak S, Miller J, Morris EC, Stewart WCL, Greenberg DA
Epilepsia 2018 May;59(5):1011-1019. Epub 2018 Apr 2 doi: 10.1111/epi.14058. PMID: 29608786 Free PMC Article

Case-control pharmacogenetic study of HCN1/HCN2 variants and genetic generalized epilepsies.

Wu SZ, Ye H, Yang XG, Lu ZL, Qu Q, Qu J
Clin Exp Pharmacol Physiol 2018 Mar;45(3):226-233. Epub 2017 Nov 28 doi: 10.1111/1440-1681.12877. PMID: 29047147

The phenotypic spectrum related to the human epilepsy susceptibility gene "EJM1".

Sander T, Hildmann T, Janz D, Wienker TF, Neitzel H, Bianchi A, Bauer G, Sailer U, Berek K, Schmitz B
Ann Neurol 1995 Aug;38(2):210-7. doi: 10.1002/ana.410380213. PMID: 7654068

See all (21)

Diagnosis

Alzheimer Disease and Epilepsy: A Mendelian Randomization Study.

Fang Y, Si X, Wang J, Wang Z, Chen Y, Liu Y, Yan Y, Tian J, Zhang B, Pu J
Neurology 2023 Jul 25;101(4):e399-e409. Epub 2023 May 24 doi: 10.1212/WNL.0000000000207423. PMID: 37225432 Free PMC Article

Myoclonic epilepsy, parkinsonism, schizophrenia and left-handedness as common neuropsychiatric features in 22q11.2 deletion syndrome.

Fanella M, Frascarelli M, Lambiase C, Morano A, Unolt M, Liberati N, Fattouch J, Buzzanca A, Accinni T, Ceccanti M, Viganò A, Biondi M, Colonnese C, Giallonardo AT, Di Fabio F, Pizzuti A, Di Bonaventura C, Berardelli A
J Med Genet 2020 Mar;57(3):151-159. Epub 2019 Sep 10 doi: 10.1136/jmedgenet-2019-106223. PMID: 31506323

Childhood Absence Epilepsy evolving to Eyelid Myoclonia with Absence Epilepsy.

Galli J, Micheletti S, Malerba L, Fazzi E, Giordano L
Seizure 2018 Oct;61:1-3. Epub 2018 Jul 18 doi: 10.1016/j.seizure.2018.07.009. PMID: 30029089

Pattern-sensitive epilepsy: electroclinical characteristics, natural history, and delineation of the epileptic syndrome.

Radhakrishnan K, St Louis EK, Johnson JA, McClelland RL, Westmoreland BF, Klass DW
Epilepsia 2005 Jan;46(1):48-58. doi: 10.1111/j.0013-9580.2005.26604.x. PMID: 15660768

Genetics of epilepsy: current status and perspectives.

Kaneko S, Okada M, Iwasa H, Yamakawa K, Hirose S
Neurosci Res 2002 Sep;44(1):11-30. doi: 10.1016/s0168-0102(02)00065-2. PMID: 12204289

See all (9)

Therapy

Alzheimer Disease and Epilepsy: A Mendelian Randomization Study.

Fang Y, Si X, Wang J, Wang Z, Chen Y, Liu Y, Yan Y, Tian J, Zhang B, Pu J
Neurology 2023 Jul 25;101(4):e399-e409. Epub 2023 May 24 doi: 10.1212/WNL.0000000000207423. PMID: 37225432 Free PMC Article

Childhood Absence Epilepsy evolving to Eyelid Myoclonia with Absence Epilepsy.

Galli J, Micheletti S, Malerba L, Fazzi E, Giordano L
Seizure 2018 Oct;61:1-3. Epub 2018 Jul 18 doi: 10.1016/j.seizure.2018.07.009. PMID: 30029089

Case-control pharmacogenetic study of HCN1/HCN2 variants and genetic generalized epilepsies.

Wu SZ, Ye H, Yang XG, Lu ZL, Qu Q, Qu J
Clin Exp Pharmacol Physiol 2018 Mar;45(3):226-233. Epub 2017 Nov 28 doi: 10.1111/1440-1681.12877. PMID: 29047147

GABRG2, rs211037 is associated with epilepsy susceptibility, but not with antiepileptic drug resistance and febrile seizures.

Balan S, Sathyan S, Radha SK, Joseph V, Radhakrishnan K, Banerjee M
Pharmacogenet Genomics 2013 Nov;23(11):605-10. doi: 10.1097/FPC.0000000000000000. PMID: 24061200

Immunological aspects of epilepsy.

Aarli JA
Brain Dev 1993 Jan-Feb;15(1):41-9. doi: 10.1016/0387-7604(93)90005-s. PMID: 8338210

See all (6)

Prognosis

Alzheimer Disease and Epilepsy: A Mendelian Randomization Study.

Fang Y, Si X, Wang J, Wang Z, Chen Y, Liu Y, Yan Y, Tian J, Zhang B, Pu J
Neurology 2023 Jul 25;101(4):e399-e409. Epub 2023 May 24 doi: 10.1212/WNL.0000000000207423. PMID: 37225432 Free PMC Article

Frequency of epilepsies in family members of patients with different epileptic syndromes.

Sozmen V, Baybas S, Dirican A, Koksal A, Ozturk M
Eur Neurol 2011;65(1):4-9. Epub 2010 Nov 25 doi: 10.1159/000322125. PMID: 21109740

Exclusion of the juvenile myoclonic epilepsy gene EFHC1 as the cause of migraine on chromosome 6, but association to two rare polymorphisms in MEP1A and RHAG.

Norberg A, Forsgren L, Holmberg D, Holmberg M
Neurosci Lett 2006 Mar 27;396(2):137-42. Epub 2005 Dec 27 doi: 10.1016/j.neulet.2005.11.039. PMID: 16378686

Pattern-sensitive epilepsy: electroclinical characteristics, natural history, and delineation of the epileptic syndrome.

Radhakrishnan K, St Louis EK, Johnson JA, McClelland RL, Westmoreland BF, Klass DW
Epilepsia 2005 Jan;46(1):48-58. doi: 10.1111/j.0013-9580.2005.26604.x. PMID: 15660768

See all (4)

Clinical prediction guides

Alzheimer Disease and Epilepsy: A Mendelian Randomization Study.

Fang Y, Si X, Wang J, Wang Z, Chen Y, Liu Y, Yan Y, Tian J, Zhang B, Pu J
Neurology 2023 Jul 25;101(4):e399-e409. Epub 2023 May 24 doi: 10.1212/WNL.0000000000207423. PMID: 37225432 Free PMC Article

GABRG2, rs211037 is associated with epilepsy susceptibility, but not with antiepileptic drug resistance and febrile seizures.

Balan S, Sathyan S, Radha SK, Joseph V, Radhakrishnan K, Banerjee M
Pharmacogenet Genomics 2013 Nov;23(11):605-10. doi: 10.1097/FPC.0000000000000000. PMID: 24061200

BRD2 and TAP-1 genes and juvenile myoclonic epilepsy.

Layouni S, Buresi C, Thomas P, Malafosse A, Dogui M
Neurol Sci 2010 Feb;31(1):53-6. Epub 2009 Dec 2 doi: 10.1007/s10072-009-0190-z. PMID: 19953286

Absence of GABRA1 Ala322Asp mutation in juvenile myoclonic epilepsy families from India.

Kapoor A, Vijai J, Ravishankar HM, Satishchandra P, Radhakrishnan K, Anand A
J Genet 2003 Apr-Aug;82(1-2):17-21. doi: 10.1007/BF02715876. PMID: 14631097

The phenotypic spectrum related to the human epilepsy susceptibility gene "EJM1".

Sander T, Hildmann T, Janz D, Wienker TF, Neitzel H, Bianchi A, Bauer G, Sailer U, Berek K, Schmitz B
Ann Neurol 1995 Aug;38(2):210-7. doi: 10.1002/ana.410380213. PMID: 7654068

See all (16)

MedGen

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Myoclonic epilepsy, juvenile, susceptibility to, 1(EJM1)

Definition

Clinical features

Term Hierarchy

Professional guidelines

PubMed

Recent clinical studies

Etiology

Diagnosis

Therapy

Prognosis

Clinical prediction guides

Supplemental Content

Table of contents

Genetic Testing Registry

Clinical resources

Practice guidelines

Molecular resources

Consumer resources

Reviews

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