Figure 1. The effects of environmental and genetic factors that may lead to inflammation and skin barrier breakdown. CSTA, cystatin-A gene; FLG, filaggrin gene, IL, interleukin; KLK7, kallikrein-related peptidase 7 gene; NMF, natural moisturising factor; PAR, protease-activated receptor; SPINK5, serine peptidase inhibitor, Kazal type 5 gene; Th, T helper cell. Reproduced with permission from Danby SG and Cork MJ, The Academic Unit of Dermatology Research, The University of Sheffield