FLG and Alzheimer disease: Although prevalent and rare loss-of-function mutations have been identified as the cause of the genodermatosis ichthyosis vulgaris and were additionally reported to be an important predisposing factor for the development of AD [44,45,46,47], our results on AD infant skin reflect the atopic diathesis as a genotypic predisposition but are not consistent with loss-of-function mutations in the gene encoding filaggrin in AD which may represent only one facet of the atopic abnormalities.