HSPA5 and amelogenesis imperfecta type 1G: In this study, dietary histidine deficiency activated the PEPK-signalling pathway and IRE1-signalling pathway with increased core gene expression of pepk, grp78, eif2α, atf4, chopα, ire1, xbp1, traf2, ask1, and jnk1, indicating that dietary histidine deficiency induced ERS.