Genetic aspects of Alzheimer's disease, Pick's disease, and other dementias.

Although genetic testing is available for some degenerative diseases, in most types of dementia, both genetic and environmental factors are involved. Overall, dementing diseases can be either sporadic or inherited, and in general, the earlier the onset, the more likely a disease is to be inherited. Before genetic testing is performed, the ethical issues, such as the effect the tests might have on asymptomatic children, should be considered. The ethical use of DNA samples in research is another genetic testing issue to be considered.