[Enzyme-and immuno-histochemistry of muscle biopsies in severe infantile spinal muscular atrophy].

The basic lesions in the muscle biopsies of 11 cases of severe infantile spinal muscular atrophy showed typical neurogenic fascicular muscular atrophy. It was found through histochemistry staining that both types of muscle fibres were involved which were characterised by the presence of type grouping of the damaged fibers, anyhow, the original mosaic pattern of both types were still partially reserved. With anti-laminin immunofluorescence staining, it was demonstrated that the basal membrane of atrophied small muscle fibre was still intact. It is considered that the main manifestation of damage on spinal anterior horn neuron is denervation of the skeletal muscle; meanwhile, the function of the muscle fibre in regulations carbohydrate metabolism is not apparently obstructs. The pathologic process of this disease develops from denervation to renervation and then back to denervation again. Therefore the clinical feature of muscle atrophy in this disease is progressive and developmental.