<p>(A) Frataxin mRNA in PBMCs and whole blood (R<sup>2</sup> = 0.84, p<0.0001). (B) Frataxin protein in PBMCs and whole blood (R<sup>2</sup> = 0.63, p<0.0001). (C) Frataxin mRNA and protein in whole blood (R<sup>2</sup> = 0.55, p<0.0001). (D) Frataxin mRNA and protein in PBMCs (R<sup>2</sup> = 0.58, p<0.0001). (E) Frataxin protein in PBMCs and cheek swabs (R<sup>2</sup> = 0.67, p<0.0001). (F) Frataxin protein in whole blood and cheek swabs (R<sup>2</sup> = 0.58, p<0.0001). Frataxin mRNA level in PBMCs and whole blood is expressed relative to control donor levels and is normalized to the endogenous control gene <i>GAPDH</i>.</p