Condition causes discomfort throughout life but is not life-threatening. Hip displacement at birth not uncommon. May be disabling. Weakness of arm, leg, trunk, face and throat muscles. Severity and progression vary.
Life expectancy is threatened.
Autosomal dominant, autosomal recessive. Drooping of upper eyelids, facial weakness, blackout spells. Weakness of the limbs and trunk muscles. Reflexes usually absent. X-linked recessive, autosomal recessive, autosomal dominant.