The phenotype of heterozygous mice subtly mirrors much of the homozygous phenotype. Complete blood count parameters (n = 15-17 mice per sex) demonstrated significant decreases in MCV in the Tf^C-bl/+ mice relative to Tf ^N-bl/+ or WT mice (A), significant decreases in MCH in Tf^C-bl/+ mice relative to Tf^N-bl/+ mice (B), and significant increases in reticulocyte count in the Tf^N-bl/+ mice relative to both Tf^C-bl/+ and WT mice (C). Tissue iron assays (n = 9-11 mice per sex) demonstrated a significant increase in hepatic iron concentration in the Tf^N-bl/+ male mice relative to Tf^C-bl/+ and WT male mice (D) and significant decreases in splenic iron in the Tf^C-bl/+ females compared with Tf^N-bl/+females and in Tf^C-bl/+ males relative to both Tf^N-bl/+ males and WT males (E). Data are presented as Tukey box and whisker plots. Statistical significance was analyzed by Kruskal-Wallis or 1-way ANOVA. *P ≤ .05, **P ≤ .01, ***P ≤ .001, ****P ≤ .0001.