ALDH1A1 and Pelizeaus-Merzbacher spectrum disorder: A similar observation was made by Visus, et al. 35 (2007), who used ALDH1 as a distinguishing marker for PMD and malignant lesions, 32 corroborating the idea that ALDH1 expression changes depending on the pathological variance of pre- and malignant lesions, and could contribute to the fast development and progression of cancer.