ENO2 and Menkes disease: The cochlear PLE enhancement ratio between the affected MD ear and contralateral asymptomatic ear was increased with the ZPE sequence (1.7049; IQR 0.72) relative to the NSE sequence (1.5010; IQR 0.52) in the 40 patients with unilateral definite MD, although this was not statistically significant (z = 2.540, p = 0.11) (Fig. 5).