EN2 and Menkes disease: When MD was performed in adult age, neither En2+/+ (n = 4; C/I ratio = 1.82 ± 0.09 vs. 1.85 ± 0.16 in non-MD conditions) nor En2−/− mice (n = 4; C/I ratio = 1.32 ± 0.07 vs. 1.36 ± 0.19 in non-MD conditions) displayed significant OD plasticity (non-MD vs. MD, Two-Way ANOVA followed by Tukey test, p > 0.05; Figure 7C).