FLG and Alzheimer disease: Skin barrier alterations are present in AD patients without filaggrin changes; however, the presence of FLG variants leading to loss of function has been associated with clinical phenotypes such as persistent early-onset disease, asthma, and allergic sensitization.1, 4 Marked ethnic disparity has been observed in the frequency of FLG variants leading to loss of filaggrin function in AD.5