Here we demonstrate the development of a cell-based HTS assay in 1,536-well plates utilizing cultured skin fibroblasts from a patient with metachromatic leukodystrophy (MLD), a LSD caused by deficiency of arylsulfatase A (ASA), resulting in severe demyelination secondary to the accumulation of sulfatide lipid in myelin [14]. This evidence concerns the gene ARSA and metachromatic leukodystrophy.