Abstract
A 4-year-6-month-old boy was noted to have muscle wasting as well as weakness in the arms and shoulders at the age of 3 years. Muscle wasting was rather nonprogressive in contrast to its relatively abrupt onset. On the examination, he demonstrated symmetrical muscle atrophy in scapulohumeral distribution with remarkable looseness of the scapulas. On traction from the supine position with hands, a complete head-lag was noted because of severe muscle weakness of the neck, shoulders and arms. His mental state was normal. There was mild facial weakness, but no recognizable “myopathic” face. Tendon jerks were diminished except for normo-active ankle jerks. Neither sensory disturbance nor fasciculation was recognized. Serum CPK level was slightly elevated, while various chemical and immunological studies for polymyositis were negative. EMG showed positive sharp waves and fibrillation potentials at rest suggesting the neuropathic process, but without apparent reinnervation motor units. Motor conduction velocity was within normal limits. The biopsy specimen from the biceps muscle of left arm revealed neurogenic atrophy including a marked variation in fiber size withsmall groups of atrophic fibers consisting of mainly type 2 fibers.
Though there have been several cases with neurogenic muscular atrophy of facioscapulohumeral type in the literature, it seems quite unusual that the symptoms have started in the early childhood as seen in the present case.
