Deficiency of arylsulfatase A (ARSA) (EC 3.1.6.8) (also due to pathogenic variants in ARSA or PSAP revealing metachromatic leukodystrophy [MLD; OMIM #250100] or SAP‐B deficiency [SAP‐B; OMIM #249900]) leads to accumulation of sulfatides causing neurodegeneration.10 This evidence concerns the gene PSAP and metachromatic leukodystrophy.