[Clinical and histochemical findings in spinal muscular atrophy]

The childhood form of the spinal muscular atrophy (SMA) is classically subdivided into three groups on the basis of a combination of age of onset, milestones of development and age of survival: acute Werdning-Hoffmann (type I), intermediate Werdnig-Hoffmann (type II) and Kugelberg-Welander disease (type III). Now we examined 7 cases of type I and 9 cases of type II on clinical and histochemical ground. Of the total of 16 cases, 5 cases had a family history of the disease. (1) In type I, three were males and 4 females. The onset was within 30 days and the disease was manifest before or at delivery in 3 cases. The progression was so severe. All cases were dead by 10 months. They showed generalized hypotonia, abnormal respiration and could not sit without support. In type II, five were males and 4 females. The onset of the disease was between the age of 3 and 15 months. The progression was slow. All patients couldn't walk by themselves at all but 7 of them had abilities to sit without support. Clinically it was easy to classify type I from type II. (2) The most characteristic histochemical findings of both types were group atrophy, fiber hypertrophy, fiber type predominance and fibrosis. Though there was a slight difference between two types in histological pattern, the basis was so similar. There is controversy about the proper classification of recessive childhood SMA. Now it is suggested that the majority of both acute and chronic cases are allelic, similar to the patterns of Duchenne and Becker forms of muscular dystrophy.