Myotonia congenita

The myotonia congenita Thomsen is an inherited disorder of muscle function, called myopathy.

The myotonia congenita is inherited as an autosomal dominant trait and is relatively rare ( 1:400,000 ). Women are often slightly lighter than men. Almost always there is a familial aggregation due to the mode of inheritance. The variation relates to a gene on chromosome 7 encoding the chloride channels of the muscle fiber membrane. The reduced chloride permeability depolarize the muscle fibers more easily than in a healthy person.

Symptom is perceived as stiffness contraction inclination (eg already by tapping ) and Erschlaffungsstörung of the muscle. The closed fist for example, can not be opened immediately. After several back and forth movement is the movement better ( warm-up phenomenon). Also striking is the so-called lid -lag, in which after up to 30 seconds to open the eyes squinting again. The occurrence and severity of symptoms vary from person to person sometimes strong. Furthermore, they are of the weather, time of day and general physical and mental shape dependent. Atrophy do not occur, on the contrary, many sufferers are strikingly athletic. This is in contrast to the hindrance of the movement, but can be generally well tolerated.

Membrane -stabilizing drugs such as Mexitil, phenytoin, carbamazepine, or quinine sulfate can improve the symptoms.