GDF15 and Menkes disease: In contrast, the ROC curve analyses between the full MD cohort vs. non-MD patients (including all individuals regardless of their age differences and clinical symptoms, Figure 2E and Table 2) showed no discriminative ability for pGSN (AUC = 0.58, IC95% (0.47; 0.70)) to distinguish between both groups, in contrast with FGF-21 (AUC = 0.77, IC95% (0.67; 0.87)) and GDF-15 (AUC = 0.76, IC95% (0.66; 0.87)) (p-value = 0.045 for global comparison between AUCs of pGSN, FGF-21, and GDF-15 plasma levels).