Abstract des Autors

Muscle cramping and stiffness are common complaints in athletes. Among the numerous causes for these complaints are the myotonias. The myotonias comprise a group of neuromuscular disorders with the characteristic symptom of uncontrollable temporary stiffness of muscle. Myotonia congenita is one of the myotonias that is nonprogressive and nondystrophic. Voluntary muscle contraction, particularly after a period of rest, provokes the distinguishing stiffness. The condition is associated with chloride channel mutations that result in a transient hyperexcitability of the muscle fiber surface membrane. We report a case of an adolescent athlete whose condition became apparent when he developed symptoms while participating in athletic activities. The diagnosis, however, was made only after provocative testing and was later confirmed by genetic testing. Verf.-Referat