Siderocytes and mf-PP in XLSA and XLPP mouse models. (A) Representative photomicrographs of Perls iron-stained peripheral blood smears of control, XLSA, and XLPP males at age 8 weeks. Arrows indicate siderocytes. The range of siderocyte frequency is indicated in the upper right of each image. Original magnification, 1000×. (B) Representative transmission electron micrographs of reticulocytes from wild-type and p.R411H mice at age 8 weeks. Note the electron-dense deposits in the p.R411H mitochondria. Original magnification, 20 000×. (C) RBC Zn-PPIX determined by hematofluorometry. (D) RBC mf-PPIX mean fluorescence intensity (MFI) determined by flow cytometry. (E) ALAS activity in control, XLSA, and XLPP mutant BM determined in vitro. The dotted line in each panel indicates the average value in control animals. For all panels, n = 3 to 10 animals per group. ∗P < .05; ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001, compared with control animals at the same age. ^#P < .05; ^##P < .01; ^###P < .001; ^###P < .0001, compared with the same mutant animals at 8 weeks. CTL, control.