HEREDITARY SPASTIC PARAPLEGIA AND HEREDITARY ATAXIA

Abstract
SINCE Seeligmüller1 described the clinical, and Strümpell2 the pathological, characteristics of hereditary spastic paraplegia, an extensive literature on the subject has developed, and clinical reviews have appeared by Rhein,3 Paskind and Stone,4 and Jackson.5 The genetic, as well as the clinical, aspects of the disorder have been analyzed by Bell and Carmichael.6 Strümpell7 originally described two varieties of spastic paraplegia, one developing in adult life, the other in childhood and associated with mental retardation. Rhein3 separated the cases in the literature into seven groups, distinguished by arbitrary anatomicoclinical criteria. Bell and Carmichael6 divided 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