Myotonia congenita Thomsen
The myotonia congenita is an inherited disorder of muscle function , a so-called myopathy .
The disease was first described in 1876 by the Danish doctor Julius Thomsen in himself and 20 other family members over four generations.
Myotonia congenita is inherited as an autosomal dominant trait and is relatively rare (1: 400,000). Women are often more easily affected than men. There is almost always a familial cluster due to inheritance . The change affects a gene on chromosome 7 that encodes chloride channels in the muscle fiber membrane. Due to the reduced permeability to chloride , the muscle fibers depolarize more easily than in a healthy person.
The main symptom is a tendency to contract, which is perceived as stiffness (e.g. already by tapping) and a relaxation disorder of the muscle. For example, the closed fist cannot be opened immediately. After repeated back and forth movements, mobility improves ( warm-up phenomenon ). Also noticeable is the so-called lid-lag , in which the eyes only open again after up to 30 seconds after squinting. The appearance and severity of symptoms can vary widely from person to person. Furthermore, they depend on the weather, time of day and general physical and psychological condition. Atrophy does not occur; on the contrary, many of those affected are noticeably athletic . This is in contrast to the hindrance to movement, which can usually be tolerated well.
Membrane-stabilizing drugs such as Mexitil , phenytoin , carbamazepine or quinine sulfate can improve the symptoms.
See also
Web links
- General presentation of the myotonia forms ( Memento from July 21, 2007 in the Internet Archive ) (PDF file; 63 kB)
Individual evidence
- ↑ J. Thomsen: Tonic cramps in voluntarily mobile muscles as a result of inherited psychological disposition: Ataxia muscularis? In: Arch Psychiatrie Nervenkrankh . tape 6 , 1876, p. 702-718 .
