With the departure of the previous PI, this project has been maintained mainly as a resource for future research to be developed in relation to a new Unit on Clinical Neurogenetics which has been established in the CNB. Inherited Alzheimer disease - longitudinal data collection, expansion of pedigree information and recruitment of additional family members, as well as counseling of numerous families, some followed since 1977, has continued. Collaborations have also continued although no patient was admitted during the past year. In September 1994, we hope to admit families with the continued collaboration of Trey Sunderland, M.D., NIMH. Longitudinal study involves LP's, PET, DNA, psychological testing, and psychological and genetic counseling.