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Myoclonus, familial, 2(MYOCL2)

MedGen UID:
1683864
•Concept ID:
C5193056
•
Disease or Syndrome
Synonyms: MYOCL2; MYOCLONUS, FAMILIAL, 2
 
Gene (location): SCN8A (12q13.13)
 
Monarch Initiative: MONDO:0100092
OMIM®: 618364

Definition

Familial myoclonus-2 is an autosomal dominant neurologic condition characterized by childhood onset of isolated action-induced nonepileptic myoclonus affecting the upper limbs. The disorder is nonprogressive (Wagnon et al., 2018). [from OMIM]

Clinical features

From HPO
Dystonic disorder
MedGen UID:
3940
•Concept ID:
C0013421
•
Sign or Symptom
An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk.
See: Feature record | Search on this feature
Seizure
MedGen UID:
20693
•Concept ID:
C0036572
•
Sign or Symptom
A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
See: Feature record | Search on this feature
Delayed ability to walk
MedGen UID:
66034
•Concept ID:
C0241726
•
Finding
A failure to achieve the ability to walk at an appropriate developmental stage. Most children learn to walk in a series of stages, and learn to walk short distances independently between 12 and 15 months.
See: Feature record | Search on this feature
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.
See: Feature record | Search on this feature
Limb myoclonus
MedGen UID:
1368754
•Concept ID:
C4477055
•
Sign or Symptom
See: Feature record | Search on this feature

Professional guidelines

PubMed

Clinical profile and treatment outcome of epilepsy syndromes in children: A hospital-based study in Eastern Nepal.
Poudel P, Kafle SP, Pokharel R
Epilepsia Open 2021 Mar;6(1):206-215. Epub 2021 Feb 8 doi: 10.1002/epi4.12470. PMID: 33681663Free PMC Article
Phenotypic and genetic spectrum of SCN8A-related disorders, treatment options, and outcomes.
Gardella E, Møller RS
Epilepsia 2019 Dec;60 Suppl 3:S77-S85. doi: 10.1111/epi.16319. PMID: 31904124
Diagnosis and management of restless legs syndrome in children.
Simakajornboon N, Kheirandish-Gozal L, Gozal D
Sleep Med Rev 2009 Apr;13(2):149-56. Epub 2009 Jan 31 doi: 10.1016/j.smrv.2008.12.002. PMID: 19186083Free PMC Article

Recent clinical studies

Etiology

Comorbidities in children with elevated periodic limb movement index during sleep.
Delrosso LM, Lockhart C, Wrede JE, Chen ML, Samson M, Reed J, Martin-Washo S, Arp M, Ferri R
Sleep 2020 Feb 13;43(2) doi: 10.1093/sleep/zsz221. PMID: 31555831
Clinical-electrophysiological correlation of tremor and myoclonus in a kindred with the N279K tau mutation.
Caviness JN, Tsuboi Y, Wszolek ZK
Parkinsonism Relat Disord 2003 Jan;9(3):151-7. doi: 10.1016/s1353-8020(02)00034-2. PMID: 12573870
Genetics of myoclonic and myoclonus epilepsies.
Minassian BA, Sainz J, Delgado-Escueta AV
Clin Neurosci 1995-1996;3(4):223-35. PMID: 8891396
First experimental transmission of fatal familial insomnia.
Tateishi J, Brown P, Kitamoto T, Hoque ZM, Roos R, Wollman R, Cervenáková L, Gajdusek DC
Nature 1995 Aug 3;376(6539):434-5. doi: 10.1038/376434a0. PMID: 7630420
Progressive myoclonus epilepsies. Criteria for diagnosis on the basis of the follow-up of 37 cases.
Guazzi GC, Federico A
Acta Neurol (Napoli) 1992 Aug-Dec;14(4-6):469-84. PMID: 1293989

Diagnosis

Geniospasm: A systematic review on natural history, prognosis, and treatment.
Teng LY, Abd Hadi D, Anandakrishnan P, Murugesu S, Khoo TB, Mohamed AR
Brain Dev 2022 Sep;44(8):499-511. Epub 2022 Jun 4 doi: 10.1016/j.braindev.2022.05.005. PMID: 35672188
Genetic Epilepsy Syndromes.
Myers KA
Continuum (Minneap Minn) 2022 Apr 1;28(2):339-362. doi: 10.1212/CON.0000000000001077. PMID: 35393962
Genetic Aspects of Myoclonus-Dystonia Syndrome (MDS).
Rachad L, El Kadmiri N, Slassi I, El Otmani H, Nadifi S
Mol Neurobiol 2017 Mar;54(2):939-942. Epub 2016 Jan 20 doi: 10.1007/s12035-016-9712-x. PMID: 26790671
Inherited movement disorders.
Harding AE
Baillieres Clin Neurol 1994 Aug;3(2):259-79. PMID: 7952847
Hereditary essential myoclonus.
Lundemo G, Persson HE
Acta Neurol Scand 1985 Aug;72(2):176-9. doi: 10.1111/j.1600-0404.1985.tb00860.x. PMID: 4050325

Therapy

Beneficial Effects of Metformin on the Central Nervous System, with a Focus on Epilepsy and Lafora Disease.
Sanz P, Serratosa JM, Sánchez MP
Int J Mol Sci 2021 May 19;22(10) doi: 10.3390/ijms22105351. PMID: 34069559Free PMC Article
Comorbidities in children with elevated periodic limb movement index during sleep.
Delrosso LM, Lockhart C, Wrede JE, Chen ML, Samson M, Reed J, Martin-Washo S, Arp M, Ferri R
Sleep 2020 Feb 13;43(2) doi: 10.1093/sleep/zsz221. PMID: 31555831
Movement disorders and other motor abnormalities in adults with 22q11.2 deletion syndrome.
Boot E, Butcher NJ, van Amelsvoort TA, Lang AE, Marras C, Pondal M, Andrade DM, Fung WL, Bassett AS
Am J Med Genet A 2015 Mar;167A(3):639-45. Epub 2015 Feb 13 doi: 10.1002/ajmg.a.36928. PMID: 25684639Free PMC Article
Electroencephalographic features of benign adult familial myoclonic epilepsy.
Toyota T, Akamatsu N, Tanaka A, Tsuji S, Uozumi T
Clin Neurophysiol 2014 Feb;125(2):250-4. Epub 2013 Sep 4 doi: 10.1016/j.clinph.2013.08.002. PMID: 24011985
Antidepressants and the serotonin syndrome in general practice.
Mackay FJ, Dunn NR, Mann RD
Br J Gen Pract 1999 Nov;49(448):871-4. PMID: 10818650Free PMC Article

Prognosis

Loss-of-function mutations in SGCE found in Japanese patients with myoclonus-dystonia.
Azuma K, Horisawa S, Mashimo H, Fukuda M, Kumada S, Kawamata T, Taira T, Akagawa H
Clin Genet 2023 Feb;103(2):209-213. Epub 2022 Oct 7 doi: 10.1111/cge.14233. PMID: 36161439
Genetic Epilepsy Syndromes.
Myers KA
Continuum (Minneap Minn) 2022 Apr 1;28(2):339-362. doi: 10.1212/CON.0000000000001077. PMID: 35393962
ADCY5-related dyskinesia presenting as familial myoclonus-dystonia.
Douglas AG, Andreoletti G, Talbot K, Hammans SR, Singh J, Whitney A, Ennis S, Foulds NC
Neurogenetics 2017 Apr;18(2):111-117. Epub 2017 Feb 22 doi: 10.1007/s10048-017-0510-z. PMID: 28229249Free PMC Article
Inherited movement disorders.
Harding AE
Baillieres Clin Neurol 1994 Aug;3(2):259-79. PMID: 7952847
Early-onset Alzheimer's disease in 2 large Belgian families.
Martin JJ, Gheuens J, Bruyland M, Cras P, Vandenberghe A, Masters CL, Beyreuther K, Dom R, Ceuterick C, Lübke U
Neurology 1991 Jan;41(1):62-8. doi: 10.1212/wnl.41.1.62. PMID: 1985297

Clinical prediction guides

Loss-of-function mutations in SGCE found in Japanese patients with myoclonus-dystonia.
Azuma K, Horisawa S, Mashimo H, Fukuda M, Kumada S, Kawamata T, Taira T, Akagawa H
Clin Genet 2023 Feb;103(2):209-213. Epub 2022 Oct 7 doi: 10.1111/cge.14233. PMID: 36161439
Promoter analysis and transcriptional regulation of human carbonic anhydrase VIII gene in a MERRF disease cell model.
Lo CM, Ma YS, Wei YH, Hsieh BYT, Hsieh M
Arch Biochem Biophys 2018 Mar 1;641:50-61. Epub 2018 Jan 31 doi: 10.1016/j.abb.2018.01.012. PMID: 29407793
ADCY5-related dyskinesia presenting as familial myoclonus-dystonia.
Douglas AG, Andreoletti G, Talbot K, Hammans SR, Singh J, Whitney A, Ennis S, Foulds NC
Neurogenetics 2017 Apr;18(2):111-117. Epub 2017 Feb 22 doi: 10.1007/s10048-017-0510-z. PMID: 28229249Free PMC Article
CACNA1B mutation is linked to unique myoclonus-dystonia syndrome.
Groen JL, Andrade A, Ritz K, Jalalzadeh H, Haagmans M, Bradley TE, Jongejan A, Verbeek DS, Nürnberg P, Denome S, Hennekam RC, Lipscombe D, Baas F, Tijssen MA
Hum Mol Genet 2015 Feb 15;24(4):987-93. Epub 2014 Oct 8 doi: 10.1093/hmg/ddu513. PMID: 25296916Free PMC Article
Inherited movement disorders.
Harding AE
Baillieres Clin Neurol 1994 Aug;3(2):259-79. PMID: 7952847

Recent systematic reviews

KCTD7-related progressive myoclonic epilepsy: Report of 42 cases and review of literature.
Yoganathan S, Whitney R, Thomas M, Danda S, Chettali AM, Prasad AN, Farhan SMK, AlSowat D, Abukhaled M, Aldhalaan H, Gowda VK, Kinhal UV, Bylappa AY, Konanki R, Lingappa L, Parchuri BM, Appendino JP, Scantlebury MH, Cunningham J, Hadjinicolaou A, El Achkar CM, Kamate M, Menon RN, Jose M, Riordan G, Kannan L, Jain V, Manokaran RK, Chau V, Donner EJ, Costain G, Minassian BA, Jain P
Epilepsia 2024 Mar;65(3):709-724. Epub 2024 Jan 17 doi: 10.1111/epi.17880. PMID: 38231304
Geniospasm: A systematic review on natural history, prognosis, and treatment.
Teng LY, Abd Hadi D, Anandakrishnan P, Murugesu S, Khoo TB, Mohamed AR
Brain Dev 2022 Sep;44(8):499-511. Epub 2022 Jun 4 doi: 10.1016/j.braindev.2022.05.005. PMID: 35672188
Movement disorders associated with neuronal antibodies: a data-driven approach.
Sturchio A, Dwivedi AK, Gastaldi M, Grimberg MB, Businaro P, Duque KR, Vizcarra JA, Abdelghany E, Balint B, Marsili L, Espay AJ
J Neurol 2022 Jul;269(7):3511-3521. Epub 2022 Jan 13 doi: 10.1007/s00415-021-10934-7. PMID: 35024921Free PMC Article
Movement Disorders in Prionopathies: A Systematic Review.
Rodriguez-Porcel F, Ciarlariello VB, Dwivedi AK, Lovera L, Da Prat G, Lopez-Castellanos R, Suri R, Laub H, Walker RH, Barsottini O, Pedroso JL, Espay AJ
Tremor Other Hyperkinet Mov (N Y) 2019;9 Epub 2019 Dec 12 doi: 10.7916/tohm.v0.712. PMID: 31871824Free PMC Article
Signs and symptoms preceding the diagnosis of Alzheimer's disease: a systematic scoping review of literature from 1937 to 2016.
Bature F, Guinn BA, Pang D, Pappas Y
BMJ Open 2017 Aug 28;7(8):e015746. doi: 10.1136/bmjopen-2016-015746. PMID: 28851777Free PMC Article

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      OMIM records containing genes associated with phenotypes registered in MedGen
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