To reconcile the different hair coat phenotypes of Scd1−/− mice and Lgr5‐Cre;Scd1fl/fl mice, we evaluated the proliferation and apoptosis of the cells in hair bulb to understand the effect of SCD1 on growth and regression of HFSCs, respectively.[24] Surprisingly, in Scd1−/− mice, although there are elongated HFs, the number of Ki67+ proliferating cells and apoptotic cells in hair bulbs were comparable to those in WT mice (Figure 2H–J), suggesting that the HF defects observed may be indirect effects. This evidence concerns the gene SCD and hydrops fetalis.