[The genetics of Alzheimer's disease].

This paper examines recent epidemiological and molecular genetic studies on the genetic basis of Alzheimer's disease (AD). Recent epidemiological studies have shown the existence of a genetic etiology in some cases of Alzheimer's disease. Several pedigrees with an increased incidence of AD (familial Alzheimer's disease--FAD) have been described in the literature. Some of these contain sufficient numbers of affected individuals in multiple generations to provide a rigorous argument for an autosomal dominant inheritance of the AD phenotype. FAD pedigrees show several evidences of as phenotypic heterogeneity of the disease. Molecular genetic studies have shown a linkage between several polymorphic DNA markers specific for the pericentromeric region of chromosome 21 and early-onset FAD. In late-onset FAD pedigrees preliminary reports showed evidence for a linkage with chromosome 19 markers. Molecular genetic studies have clearly demonstrated the genetic heterogeneity of familial Alzheimer's disease. The analysis of new, multigenerational pedigrees with FAD and the study of patients with Down's syndrome and Alzheimer's disease should provide useful informations for the characterization of the gene(s) responsible for familial Alzheimer's disease.