C4B and familial hyperaldosteronism: As in the entire FH group, in both subgroups also we confirmed a significant reduction in almost all proteins responsible for iron transportation into the cell: DMT-1 (ng/mg; NFH 5.8 ± 1.1 vs. FH-NID 4.2 ± 0.5 vs. FH-ID 4.4 ± 0.6; p < 0.0001); L-CH (ng/mg; NFH 67.3 ± 23.2 vs. FH-NID 43.1 ± 7.4; p < 0.004); TfR-1 (ng/mg; NFH 173.0 ± 36.5 vs. FH-NID 153.5 ± 31.22; p = 0.0093); also proteins responsible for iron storage FT-L (ng/mg; NFH 22.1 ± 7.4 vs. FH-NID 17.0 ± 6.5 vs. FH-ID 12.2 ± 5.5; p < 0.0002); and FT-MT (ng/mg; NFH 55.9 ± 12.4 vs. FH-NID 34.8 ± 6.0 vs. FH-ID 44.0 ± 4.4; p < 0.0001).