RÉSUMÉ
Brain biopsies for neurodegenerative disease performed at The Hospital for Sick Children, Toronto, over a 12-year period (1964 to 1976) were reviewed. Of 64 biopsies, major histologic abnormalities with diagnostic or prognostic significance comprised 39% of the total cases, minor abnormalities represented 13%, and 48% appeared normal. The procedure failed to provide prognostic assistance in 41%. With the advent for newer diagnostic techniques (enzyme assays and muscle, skin, peripheral nerve, rectal, and appendix biopsies) for neurodegenerative disease in childhood, a much lower yield is noted (15 to 20%). Only two progressive degenerative childhood conditions remain in which cerebral tissue is necessary for diagnosis--Alexander disease and Canavan spongy degeneration.