Related Experiment Video
Updated: Aug 7, 2026

In Vivo Electrophysiological Measurement of Compound Muscle Action Potential from the Forelimbs in Mouse Models of Motor Neuron Degeneration
Published on: June 15, 2018
Paralysis periodica paramyotonica caused by SCN4A Arg1448Cys mutation
Wei-Chih Hsu1, Yung-Chuan Huang, Chung-Wei Wang
1Department of Neurology, Shin-Kong WHS Memorial Hospital, Fu-Jen Catholic University, Taipei, Taiwan.
Abstract:
Paralysis periodica paramyotonica is an overlapping disease that shares the features of paramyotonia characteristic of paramyotonia congenita (PC) and periodic paralysis characteristic of hyperkalemic periodic paralysis. We report the case of a 23-year-old man with paralysis periodica paramyotonica. His father and a younger brother also exhibited a similar phenotype. A SCN4A Arg1448Cys mutation was detected in this family. The affected family members exhibited marked shifts in compound muscle action potential amplitudes on exercise test, and muscle weakness could be induced by potassium loading and cold exposure. This case demonstrates that SCN4A Arg1448Cys can produce paralysis periodica paramyotonica. Other genetic or environmental factors may modulate the manifestation of SCN4A Arg1448Cys mutation.
Related Concept Videos
Alterations in Muscle Tone lll
Tetanus
Botulism
Alterations in Muscle Tone ll
Myasthenia Gravis: Diagnostic Tests
The edrophonium test is a diagnostic tool for myasthenia gravis. It involves...
Chemical Synapses
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...

