Personal view-implications of predictive genetic testing for Alzheimer's disease

Alzheimer's disease is the commonest single cause of adult dementia, and is increasing in importance as a publichealth issue as the age structure of industrial societies changes. Perhaps 40% of Alzheimer's disease is familial; and although at least four different loci have been implicated, it is fairly likely that the genetic defects responsible will have been defined fully by the end of the millennium. This will place great pressure on clinical genetics services to perform predictive genetic testing on "at risk" individuals; but this will raise a number of psychological, social, and ethical problems, especially in the absence of preventative or curative treatment. Many of these dilemmas have already been faced in the context of screening for Huntington's disease, and are discussed in the light of this experience. The logistic problems involved in predictive testing for Alzheimer's disease will also be considerable. It would seem desirable that these issues are considered in advance, and that reasonable guidelines for testing are discussed and agreed upon before problems due to inconsistent approaches arise.