Types of muscle channelopathies
There are 2 main groups of muscle channelopathy: the non-dystrophic myotonias where patients primarily have stiffness and Periodic paralysis where patients mainly have episodes of weakness.
Mutations of different genes are responsible for these conditions but there is a significant amount of phenotypic and genotypic variability between patients making these disorders difficult to diagnose.
Non-dystrophic myotonias
The non-dystrophic myotonias are characterised by the presence of stiffness. They have clinical and electrical myotonia. There are 2 main types:
- Myotonia congenita (MC)
- Paramyotonia congenita.(PMC)
Which type a patient has is determined by which gene is affected.
Periodic Paralysis
The periodic paralyses are characterised by episodic weakness that is triggered by a change in potassium levels. There are 3 main types:
- Hyperkalaemic periodic paralysis (HyperPP)
- Hypokalaemic periodic paralysis (HypoPP)
- Andersen-Tawil syndrome.(ATS)
