Experimental evidence has been obtained that mutations in the presenilin 1 (PS1) gene in familial Alzheimer's disease can lead to the disturbance of cell adhesion in model cell cultures. It was shown that, in L fibroblasts of mice with stable expression of GFP-PS1 cDNA containing G209V or E319G mutations, cell-cell interactions and the accumulation of GFP-PS1 cDNA in intercellular contacts are disturbed. Similar results were obtained in transfected human epithelial Hep2 cells. It is assumed that mutations in familial Alzheimer's disease lead to the disturbance of the functions of presenelin 1 in cell adhesion.