KRT9 and Alzheimer disease: Our bioinformatics analysis identified that three Reactome pathways for the FLG gene are related to developmental biology and include nervous system development (https://reactome.org/PathwayBrowser/#/R-HSA-1266738, accessed on 3 May 2022), formation of the cornified envelope, which is involved in axonal regeneration [56], and keratinization (Keratin 9 has been identified as an important biomarker for AD [57]).