The present invention describes the identification, isolation, sequencing and characterization of two human presenilin genes, PS-1 and PS-2, mutations which lead to Familial Alzheimers Disease. Also identified are presenilin gene homologues in mice, C. elegans and D. melanogaster. Nucleic acids and proteins comprising or derived from the presenilins are useful in screening and diagnosing Alzheimers Disease, in identifying and developing therapeutics for treatment of Alzheimers Disease, and in producing cell lines and transgenic animals useful as models of Alzheimers Disease.
