“Status myotonicus” in Nav1.4-M1592V channelopathy

The gene SCN4A codes for the voltage-gated muscle sodium channel Nav1.4. Muscle channelopathies due to SCN4A mutations can present with varying degrees of muscle pain, stiffness and myotonia as well as with episodic attacks of myotonia (potassium-aggravated myotonia) or flaccid muscle weakness (potassium-sensitive periodic paralysis) triggered by fluctuation in the potassium level [1,2]. Here we report a case of potassium-aggravated myotonia due to Nav1.4-M1592V channelopathy with severe and long-lasting focal attacks of myotonia resembling dystonic posturing.

Source: Neuromuscular Disorders - March 11, 2020 Category: Neurology Authors: Torge Rempe, S.H. Subramony Tags: Case report Source Type: research