ARSA and leukodystrophy: Two LSDs, Krabbe disease, caused by deficiency of β-galactocerebrosidase (GALC), and Metachromatic leukodystrophy (MLD), caused by deficiency of arylsulfatase A (ARSA), belong to the class of leukodystrophies, manifesting with white matter pathology and progressive degeneration of myelin sheaths (Maegawa, 2019).