AREG and Hyperkeratosis: Using CRISPR/Cas9-mediated targeting and homology-directed repair in C57BL/6J zygotes, we recently generated mice carrying the human TOC mutation p.P189L (p.P159L in mice) in RHBDF2 (Figure 1A, top and middle panels, Figure 1B) and showed that the Rhbdf2P159L GOF mutation enhances AREG secretion to cause alopecia, rapid cutaneous wound healing, hyperplasia, and hyperkeratosis (Hosur et al., 2017a).