Proximal spinal muscular atrophy in children and young people. Clinical and genetic contribution based on 20 cases

The authors report the genetic features the clinical evolution and the histochemical data of ten patients with intermediate spinal muscular atrophy (aged from five to fourteen years) and of ten patients with juvenile spinal muscular atrophy (aged from eleven to thirty-four years.) The AA point out the lack of a net clinical and genetic distinction between these two diseases. In the same sibship both acute case and intermediate case of infantile muscular atrophy are described. In a patient with Kugelberg-Welander disease, we had to exclude a myotonic syndrome as differential diagnosis. Large type grouping and predominance of type II fibers were found in the most benign juvenile spinal muscular atrophy.