A case is described with the characteristic clinical features of rigid spine syndrome: childhood onset in a male, very slowly progressive weakness and muscle atrophy, limitation of neck and trunk flexion, joint contractures, normal intelligence, no clear family history, increased serum CPK levels and myopathic patterns in EMG and muscle biopsy specimens. Myopathic patterns with various histological changes in muscle biopsy specimens were seen in all eight reported cases of the rigid spine syndrome, but there are no characteristic histological findings in the rigid spine syndrome.