Schwartz-Jampel syndrome is a rare autosomal recessive disorder characterized by clinical myotonia, persistent spontaneous activity, and skeletal dysplasia (short stature, pigeon breast, micrognathia etc.). We experienced an eleven- year-old girl complaining of gait disturbance and motor weakness of both legs. She was operated for umblical hernia at the age of two and for congenital hip dislocation at the age of six. She displayed short stature, short neck, microstomia, micrognathia, pigeon breast, and calf musclehypertrophy. Her muscle strength was fair to good grade in both legs. Percussion- and exercise-induced myotonia was observed. Her cognitive function was below-average intelligence. Serum creatine kinase was elevated three to four times of normal level. Routine motor and sensory conduction studies were normal and continuous electrical myotonic discharges were detected in all examined muscles. Clinically, her symptom was non-progressive for three years. (J Korean Acad Rehab Med 2004; 28: 613-617)
