FLG and acrodermatitis enteropathica: Both single- and double-allele loss-of-function mutations in FLG strongly predispose to the development of atopic eczema (AE) and secondary atopic conditions, including asthma and allergic rhinitis.2, 3, 4 To date, more than 40 different population-specific FLG mutations have been identified, each resulting in a truncated profilaggrin gene product, which is not processed into functional FLG monomers.3