To test the role of PS1 in Aβ42 production and find out new drug and gene therapy for AD, in the present study IMR-32 cells were transfected with siRNA against PS1gene, and in order to interfere with transcription of PS1 gene, and then determined the levels of PS1 mRNA, PS1 and Aβ42 protein levels. This evidence concerns the gene PSEN1 and Alzheimer disease.