[Familial presenile dementia: Gerstmann-Sträussler-Scheinker's syndrome (author's transl)].

: A similar affection has developed in eight members from four generations of a family living in the Alsace. The disease is characterized by the onset of a pyramidal, pseudobulbar syndrome and dementia during the third or fourth decade of life. The outcome is fatal after a mean period of three years. Cerebral biopsies in three cases have demonstrated multicentric amyloid plaques differing from senile plaques. Clinical and pathological findings are similar to those currently reported in the literature as being typical of Gerstmann-Straussler-Scheinker's syndrome. The affection appears as a separate entity: the multicentric plaques, clinical symptomatology, pyramidal or pseudobulbar, cerebellar syndromes, usually preceding dementia, age of onset, course, and familial character or the disorder distinguish it among presenile dementias. Its clinical profile and course are very similar to that of familial cases of Alzheimer's disease, some of which are probably cases of Gerstmann-Strassler-Scheinker's syndrome. Transmission to animals, though inconstant, places it within the group of transmissible dementias among kuru, Creutzfeldt-Jakob's, and familial forms of Alzheimer's disease. The familial nature of the affection and the variability of clinical and pathological features in the same family illustrate the complex relationships between hosts and pathogenic agents in the clinicopathological expression of a disease.