FLG2 and Alzheimer disease: The strong relationship between FLG mutation status and NMF implies that the role of other histidine-rich barrier proteins, such as the S100-fused proteins, including filaggrin-2 and hornerin, that are thought to have synergistic roles with filaggrin, including contribution to NMF levels,33-35 are unlikely to play a major role in the total NMF seen in AD patients.