IGF1 and pachyonychia congenita: Signaling through Wnt Gerdes et al. (2007), Notch (Ezratty et al., 2011), Hh (Huangfu et al., 2003), G-protein-coupled receptors (GPCRs) (Schou et al., 2015), TGF-β (Clement et al., 2013), and insulin-like growth factor-1 (IGF-1) (Yeh et al., 2013) has been associated with PC.