Natural moisturizing factor as a biomarker for filaggrin mutation status in a multi‐ethnic paediatric atopic dermatitis cohort

Filaggrin is one of the main skin proteins. Loss-of-function mutations of the filaggrin gene (FLG) lead to a much-increased risk of developing atopic dermatitis (AD). AD-patients with a FLG-mutations also tend to follow a more severe disease course and have a higher risk of co-morbidities. Over 50 different mutations have been identified, with the prevalence of specific mutations being geographically and ethnically determined. In the stratum corneum, filaggrin is enzymatically degraded into its constituting amino acids and amino acid derivatives, which form the bulk of the so-called natural moisturizing factor (NMF). Its hygroscopic properties keep the stratum corneum moisturized. The paper by Van Mierlo et al. shows that a simple and quick non-invasive determination Raman-analysis of the NMF-concentration in the stratum corneum on the palm of the hand, robustly predicts the presence of filaggrin mutations, independent of the specific FLG-mutation and not affected by actual disease status.