RET and microcytic anemia: As reported in the Table S2, the msk/msk showed lower MCV compared to msk/wt (30.36 ± 3.58 fL vs. 44.73 ± 1.80 fL) indicating a microcytic anemia; in addition, the level of the reticulocyte hemoglobin content (Ret‐He) was reduced in all the ages analyzed (3–9 to 15–28 weeks) of msk/msk male and female mice (11.21 ± 0.80 pg vs. 16.65 ± 0.82 pg).