Spinal muscular atrophy type II

Abstract

A form of spinal muscular atrophy (S. M. A.) intermediate in severity between the infantile (Werd‐nig‐Hoffmann or type I) and juvenile (Kugelberg‐Welander or type III) forms of this disease has been defined. This is referred to as intermediate or type II S. M. A. and is characterized by proximal muscle weakness with onset usually between 3 and 15 months and survival beyond 4 years and usually into adolescence or later. The finclings in 14 patients with this type of S. M. A. are described. It seems possible that it is inherited as an autosomal recessive trail.