EEA1 and metachromatic leukodystrophy: Increased expression of the cis-Golgi matrix protein GM130 and of the early endosome antigen 1 (EEA1) protein (Fig. 1d) in MLD iPSCs may link lysosomal expansion to impaired endo-lysosomal trafficking33 and consequent production of reactive oxygen species (ROS)34 (Fig. 1e).