FADS1 and Alzheimer disease: In addition, we observed upregulation of the FADS1 mRNA expression in the cells (Figure 8J), likely due to a compensatory nature in the 2D model, but downregulation of the FADS1, FADS2, and FADS6 mRNA in the skin of patients with AD, suggesting more complex regulation of these enzymes during the stratification process (Figures 8K–N).