Nai et al. (2010) reported that Tmprss6 heterozygous knockout mice are more susceptible to iron deficiency compared to their wild-type littermates. Finberg et al. (2011) also demonstrated that, compared to mice deficient for Hfe alone, heterozygous loss of Tmprss6 in Hfe knockout mice had higher hepcidin levels at 4 weeks of age, which presumably resulted in decreased hepatic iron concentrations at 8 weeks of age. The gene discussed is TMPRSS6; the disease is Iron deficiency anemia.