CCL27 and Menkes disease: Linear regression also showed that there were significant negative correlations between the time of the last attack and PDGFBB (Fig. 4), and positive age-related correlations of CTACK (R2 = 0.394, p < 0.001) and MIG (R2 = 0.276, p < 0.001) expression in the MD group (p < 0.01, ANOVA) but not in the control group (Fig. 5).