mRNA expression of skin barrier proteins, such as KRT5, filaggrin (FLG), loricrin (LOR), or other AD associated genes such as semaphorin 3A (SEMA3A) and kallikrein 5 and 7 (KLK5, KLK7), showed a trend to be upregulated. The gene discussed is KRT5; the disease is Alzheimer disease.