Hereditary Spastic Paraplegia and Hereditary Ataxia

SINCE Seeligmüller1described the clinical, and Strümpell2the pathological, characteristics of hereditary spastic paraplegia, an extensive literature on the subject has developed, and clinical reviews have appeared by Rhein,3Paskind and Stone,4and Jackson.5The genetic, as well as the clinical, aspects of the disorder have been analyzed by Bell and Carmichael.6 Strümpell7originally described two varieties of spastic paraplegia, one developing in adult life, the other in childhood and associated with mental retardation. Rhein3separated the cases in the literature into seven groups, distinguished by arbitrary anatomicoclinical criteria. Bell and Carmichael6divided these hereditary diseases into two major genetic classes, showing recessive and dominant characteristics. respectively. Each class was further subdivided into types, designated as Friedreich's ataxia (hereditary sclerosis, spinal form), spastic ataxia, and spastic paraplegia, the last designation being justified only by the absence of ataxia. These authors believed