These genes include PRR9 [log2 (fold change) of 2.32]; SPRR2E [log2 (fold change) of 2.15]; SPRR1A [log2 (fold change) of 2.06]; SPRR2D [log2 (fold change) of 1.87]; SPRR3 [log2 (fold change) of 1.74], which is reduced in AD skin and inversely correlated with pruritis (itch) in non-lesional AD skin (26); and FLG (log2 (fold change of 1.77). Here, PRR9 is linked to Alzheimer disease.