Comparing lesional PN skin to lesional AD skin and control skin, the significantly upregulated DEGs in PN included matrix metalloproteinases (MMP1, MMP3, MMP10, MMP13), OSM, NGF, IL1α, IL1β, CXCL2, CXCL8, and insulin-like growth factors (IGFL2, IGFL3) (Figure 2D and Supplementary Figure 1B). The gene discussed is MMP1; the disease is Alzheimer disease.