While HF regeneration was completely inhibited in Mcl‐1 knockout mice, hair regrowth was observed in K5‐CreER/Mcl‐1f/f with Bim–/– mice, though not to the level of Mcl‐1f/f or Mcl‐1f/+ control littermates (Fig. 7B, C). This evidence concerns the gene BCL2L11 and hydrops fetalis.