KCC3 is the dominant K‐Cl cotransporter of normal mouse red blood cells (RBC) (Rust et al., 2007) and in RBC of mouse models of sickle cell disease and β‐thalassemia (Rust et al., 2007; Shmukler et al., 2019, 2020). Here, SLC12A6 is linked to sickle cell disease.