Ectopic HF can also be generated upon transient activation of epidermal β‐catenin (Lo Celso et al, 2004; Silva‐Vargas et al, 2005), in particular in Lrig1‐positive and Lgr6‐positive stem cell (SC) populations of the upper pilosebaceous unit (Kretzschmar et al, 2016). Here, LRIG1 is linked to hydrops fetalis.