The genetic aetiology of alzheimer's disease

Epidemiological studies have identified a positive family history of Alzheimer's disease (AD) as a major risk factor for the development of the disease. The results of recent family studies to determine the proportion of AD which is familial are reviewed and possible reasons for the discrepancies discussed. All these studies are consistent with a significant number of cases being caused by a dominantly inherited defect in an autosomal gene. The evidence for genetic linkage between AD and markers on the long arm of chromosome 21 in families multiply affected by disease is presented as well as discussion about the generality of this linkage and its relationship to sporadic AD.