Thomsen disease

Overview
Thomsen disease, a form of Myotonia congenita, is a muscular genetic disorder characterized by muscle stiffness (cramp) and an inability of the muscle to relax after a voluntary contraction. The affected muscle functions normally after a few repetitions.

Causes
It is associated with mutations in the chloride channel gene.

Presentation
The disorder only affects voluntary muscles, so involuntary muscles such as the heart or muscles involved in the digestion process are not affected.

Treatment and prognosis
There is no known cure but some drugs may relieve symptoms. These include: Dilantin, Procainamide, Phenytoin and Mexiletine.

The disease is not fatal.

History
Julius Thomsen, a Danish physician, was the first to describe the disease, citing symptoms of his own family members.