Disease Information

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)