As a consequence of increased ADAM17 activity, tylosis-derived keratinocytes show several features of “constitutive wound healing” in vitro, including rapid closure in scratch-wound assay, and upregulated shedding of ADAM17-dependent substrates such as EGFR-family ligands and TNFα [13]. Here, TNF is linked to Non-epidermolytic palmoplantar keratoderma.