The combined and variable deficiency of all cellular sulfatases leads to a complex clinical presentation in MSD patients with signs of single sulfatase deficiencies like metachromatic leukodystrophy (MLD), several mucopolysaccharidosis subtypes (MPS II, IIIa, IIId, IVa, VI), X‐linked recessive chondrodysplasia punctata type 1 (CDPX1), and X‐linked ichthyosis (XLI) (Adang et al, 2020; Cappuccio et al, 2020; Schlotawa et al, 2020; Verheyen et al, 2021). Here, ARSL is linked to metachromatic leukodystrophy.