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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): 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.
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.
Morning myoclonic jerks
MedGen UID:
335620
Concept ID:
C1847164
Finding
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.
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.
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.
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.

Professional guidelines

PubMed

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

Recent clinical studies

Etiology

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: 37225432Free PMC Article
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
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: 29608786Free PMC Article
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
Kinirons P, Rabinowitz D, Gravel M, Long J, Winawer M, Sénéchal G, Ottman R, Cossette P
Epilepsy Res 2008 Nov;82(1):21-28. Epub 2008 Aug 23 doi: 10.1016/j.eplepsyres.2008.06.011. PMID: 18723325Free PMC Article

Diagnosis

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: 37225432Free PMC Article
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
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
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
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

Therapy

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: 37225432Free PMC Article
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
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
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
Aarli JA
Brain Dev 1993 Jan-Feb;15(1):41-9. doi: 10.1016/0387-7604(93)90005-s. PMID: 8338210

Prognosis

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: 37225432Free PMC Article
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
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
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

Clinical prediction guides

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: 37225432Free PMC Article
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
Singh B, Monteil A, Bidaud I, Sugimoto Y, Suzuki T, Hamano S, Oguni H, Osawa M, Alonso ME, Delgado-Escueta AV, Inoue Y, Yasui-Furukori N, Kaneko S, Lory P, Yamakawa K
Hum Mutat 2007 May;28(5):524-5. doi: 10.1002/humu.9491. PMID: 17397049
Weiss LA, Escayg A, Kearney JA, Trudeau M, MacDonald BT, Mori M, Reichert J, Buxbaum JD, Meisler MH
Mol Psychiatry 2003 Feb;8(2):186-94. doi: 10.1038/sj.mp.4001241. PMID: 12610651
Sander T, Kretz R, Williamson MP, Elmslie FV, Rees M, Hildmann T, Bianchi A, Bauer G, Sailer U, Scaramelli A, Schmitz B, Gardiner RM, Janz D, Beck-Mannagetta G
Acta Neurol Scand 1997 Jul;96(1):1-7. PMID: 9262125

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