juvenile myoclonic epilepsy (of Janz)
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Epidemiology
- begins in healthy individuals between 8 & 20 years of age
- one of the most common forms of generalized epilepsy in adults[1]
Genetics
- linked to a marker on chromosome 6
- associated with defects in GABRA1
- often a family history of similar seizures
- type 1 associated with defects in EFHC1 gene
- associated with defects in CACNB4
Clinical manifestations
- manifestations begin in adolescence (type 1)
- myoclonic jerks, ranging from
- generalized tonic-clonic seizures
- myoclonic jerks & seizures generally occur after awakening
- absence seizures may also occur
- early morning clumbsiness may be reported
- symptoms triggered by sleep deprivation & fatigue
- symptoms may be triggered by alcohol[1]
Diagnostic procedures
- electroencephalogram (EEG)
- generalized spikes, 4-6 Hz spike wave complexes & multiple spike discharges
- EEG not useful in assessing need for continuation of anticonvulsants in patients who respond to combination of 2 anticonvulsants[1]
Management
- responds well to valproic acid
- lifelong anticonvulsant therapy[1]
- lifelong therapy of at least 2 anticonvulsants in patients who respond to combination of 2 anticonvulsants[1]
More general terms
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Medical Knowledge Self Assessment Program (MKSAP) 11, 15, 16, 17, 18, 19. American College of Physicians, Philadelphia 1998, 2009, 2012, 2015, 2018, 2021.
Medical Knowledge Self Assessment Program (MKSAP) 20 American College of Physicians, Philadelphia 2025 - ↑ OMIM https://mirror.omim.org/entry/606904
- ↑ Genton P, Gelisse P. Juvenile myoclonic epilepsy. Arch Neurol. 2001 Sep;58(9):1487-90. PMID: https://pubmed.ncbi.nlm.nih.gov/11559326
- ↑ Myers KA. Genetic epilepsy syndromes. Continuum (Minneap Minn). 2022;28:339-362. PMID: https://pubmed.ncbi.nlm.nih.gov/35393962