Given the absence of liver Mn excess and polycythemia in SLC39A14 deficiency, we determined the impact of Slc39a14 deficiency on Slc30a10–/– mice by generating and characterizing Slc30a10- and Slc39a14-deficient mice (Slc30a10–/– Slc39a14–/–) (Supplemental Figure 1, A and B; supplemental material available online with this article; https://doi.org/10.1172/jci.insight.169738DS1). Here, SLC39A14 is linked to polycythemia.