While these studies have firmly established Elf5 as a crucial regulator of cell fate determination of epithelial tissues, there has been very limited information of the expression and function of Elf5 in skin and HFs [10–12] and no knowledge if Elf5 is involved in the activities of epidermal and HF stem cells (SCs) and their progenies. Here, ELF5 is linked to hydrops fetalis.