Specifically, the average filaggrin levels (± SEM) in the patients sera with AD (n = 130), AR (n = 120), BA (n = 145) and their respective non-atopic controls (n = 410) were 9.36 ± 0.87, 6.50 ± 0.36, 8.50 ± 0.32 and 3.21 ± 0.13 ng/ml, respectively (Fig. 1b–d). Here, FLG is linked to Alzheimer disease.