CD34 and hydrops fetalis: Similarly, the non‐defined HF keratinocyte population (Lin–/CD49f+/CD34–/SCA‐1–) was significantly diminished in K5‐Cre/Mcl‐1f/f mice at p90, while the IFE keratinocyte subpopulation (Lin–/CD49f+/CD34–/SCA‐1+) increased significantly, correlating with complete HF loss (Fig. 3A, B).