TMPRSS6 and microcytic anemia: We found that the zebrafish mtp2 morphant embryo exhibits increased hepcidin transcript levels relative to the size of its liver and that this effect on hepcidin expression is not impaired by knockdown of hjv. This contrasts with mouse models in which crossing mice deficient in matriptase-2 with mice deficient in hjv suppresses elevated hepcidin (HAMP) transcript levels and the microcytic anemia associated with matriptase-2 deficiency in mice 9–15 weeks of age.[42]