[Intermediate forms of infantile spinal amyotrophy. Apropos of 20 personal observations].

The authors report 20 cases of infantile spinal amyotrophy, including 8 sporadic and 12 familial. There were 10 boys and 10 girls, the age of onset of the disease being between 1 and 5 years, with an average of 32 months. The clinical course is such that these forms may be easily distinguished from the classical Werdnig-Hoffman syndrome, by virtue of their later onset and their slower progression. Intermediate forms also differ from the Kugelberg-Welander pseudo-myopathic form in developing earlier and having a less benign clinical course. These features favour the existence of a series of intermediate forms situated between the two classical types, the definition and limitations of the infantile spinal amyotrophies being relatively imprecise.