Recent years have seen considerable progress in understanding the genetic basis of many diseases. There has also been a welcome and informed public debate regarding the ethical and social implications of genetic research, including predictive testing of adult onset illnesses. The UK Huntington's Prediction Consortium, a forum open to scientists, clinicians and representives from patient organisations, has established protocols for testing and has facilitated development of clinical genetic services. It has been suggested that the Huntington's disease experience might prove informative for other conditions, and a meeting was held on 5 January 1994 at the Institute of Psychiatry, London, to discuss recent research findings and possible genetic testing in Alzheimer's disease (AD). Professionals from a number of disciplines took part along with representatives of the Alzheimer's Disease Society. It was decided to form a consortium that would meet regularly and produce guidelines for future clinical applications of possible genetic tests.