Characterization of the GLRX5 mutations and functional studies in PBMCs of a healthy control, the patient, and the patient’s brother, who is heterozygous for the K101Q mutation. (A) Two compound heterozygous missense mutations were identified in the GLRX5 gene. (B) K101 is highly conserved from yeast to humans, whereas L148 in GLRX5 is conserved in Drosophila, zebrafish, chickens, and higher mammals and is replaced by amino acids with similar properties in mouse and rat. (C) Determination of IRP1 status by nondenaturing polyacrylamide gel electrophoresis. A decreased Fe-S-IRP1 protein level was observed in PBMCs of the proband. (D) Relative cytosolic aconitase activity (results expressed as the mean percentage of the aconitase activity in the PBMCs of the healthy control). (E) Western blotting of TfR1, H-ferritin, and FECH. Equal loading was confirmed by showing that COX IV and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) levels were unchanged. C, healthy control; P, patient; BP, patient's brother.