The Journal of Neuroscience, September 15, 2002, 22(18):8193-8200
Paroxysmal Dyskinesias in the Lethargic Mouse Mutant
Zubair
Khan and
H. A.
Jinnah
Department of Neurology, Johns Hopkins Hospital, Baltimore,
Maryland 21287
Lethargic mutant mice carry a mutation in the CCHB4
gene, which encodes the
4 subunit of voltage-regulated
calcium channels. These mutants have been shown to display a complex
neurobehavioral phenotype that includes EEG discharges suggestive of
absence epilepsy, chronic ataxia, and hypoactivity. The current studies
demonstrate a fourth element of their phenotype, consisting of
transient attacks of severe dyskinetic motor behavior. These attacks
can be triggered by specific environmental and chemical influences,
particularly those that stimulate locomotor activity. Behavioral and
EEG analyses indicate that the attacks do not reflect motor epilepsy,
but instead resemble a paroxysmal dyskinesia. The lethargic mutants
provide additional evidence that calcium channelopathies can produce
paroxysmal dyskinesias and provide a novel model for studying this
unusual movement disorder.
Key words:
lethargic; mouse mutant; calcium channel; channelopathy; paroxysmal dyskinesia; movement disorder; epilepsy
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