Muscle nuclear size in neuromuscular disease.

Nuclear size has been estimated in muscle biopsy specimens from seven healthy individuals, eight patients with infantile spinal muscular atrophy (types I and II), and eight patients with Duchenne muscular dystrophy. The results indicate a great increase in nuclear size in Duchenne muscular dystrophy but not in spinal muscular atrophy when compared with controls. The reasons for this finding are discussed in relation to the pathogenesis of these two groups of diseases.