TMPRSS6 and anemia: TMPRSS6 is expressed in the liver and plays an essential role in regulating the expression of the main regulator of iron homeostasis hepcidin; mutations in Tmprss6 induce high hepcidin levels, which cause iron-refractory iron deficiency anemia (Finberg et al., 2008; Nai et al., 2016; Al-Jamea et al., 2021).