Muscle stiffness and difficulty in moving after periods of rest. With exercise, muscle strength and movement return to normal. Condition causes discomfort throughout life but is not life-threatening. Drooping of upper eyelids, facial weakness, foot drop and some weakness of the limbs and trunk are common symptoms. Patients almost always have no reflexes.
Diseases progresses slowly.
Hypotonia and weakness of arm, leg, trunk, face and throat muscles. In severe cases, children have marked respiratory weakness. Children rarely survive more than a few years, yet some live into teens. Poor or difficult relaxation of muscle which usually worsens after repeated use or exercise. Condition causes discomfort throughout life but is not life-threatening.