Psychosine (Galactosylsphingosine), a substrate of the galactocerebrosidase (GALC) enzyme, is a potential biomarker for Krabbe disease. Psychosine is a highly cytotoxic lipid, capable of inducing cell death in a wide variety of cell types including, most relevantly to globoid cell leukodystrophy (GLD), oligodendrocytes. Psychosine causes cell death at least in part via apoptosis. Psychosine also is an inhibitor of PKC.In Vitro: Psychosine, is a substrate of the GALC enzyme that shows promise to aid in the diagnosis and follow-up of at-risk infants identified through newborn screening (NBS). Psychosine induces pleiotropic effects, including dysfunctions in several cellular pathways[2].