Currently, several studies have reported decreases in ceramides [8], alterations in filaggrin expression [9], and higher expression of the enzymes involved in filaggrin metabolism (such as calpain-1, caspase 14, and matriptase) [10,11] and increased Transepidermal Water Loss (TEWL) in dogs with AD [12]. The gene discussed is FLG; the disease is Alzheimer disease.