Myotonia refers to a condition in which muscles are slow to relax after contracting. This is a characteristic of a number of conditions, including:

  • myotonic dystrophy
  • myotonia congenita
  • paramyotonia congenita

As myotonic dystrophy is a distinct condition of which myotonia is only a part there is a separate area on this website about it: see the myotonic dystrophy home page. The other two conditions are covered here, as myotonia is the main and often the only symptom.


The main complaint of myotonia congenita is that the muscles don't relax after contracting. Myotonia frequently happens after long periods of rest, for example it may be physically difficult to get out of bed in the morning. The cold, tiredness or emotional stress can also trigger it. Most often it affects limb muscles but sometimes it can affect the face muscles, making it difficult to open the eyelids.

Most people with myotonia congenita learn to cope with the condition by working off the myotonia through repeated movements. Avoiding the cold also helps.

There are two types of myotonia congenita, both of which are inherited. Becker myotonia congenita is inherited as an autosomal recessive trait. Thomsen myotonia congenita - a less common form of the condition - is inherited as an autosomal dominant trait.

Paramyotonia congenita usually affects the face and hands, but may also affect the rest of the body, particularly when it is exposed to the cold. Muscle stiffness can worsen with exercise. The condition is evident from childhood but it is not progressive and does not usually require any treatment. It is inherited as an autosomal dominant trait.

Back to the the myotonias home page.