Psychosine

Psychosine, also known as galactosylsphingosine, is a lysosphingolipid that represents the deacylated form of galactosylceramide (galactocerebroside). In human tissues, psychosine occurs at low levels as part of normal sphingolipid turnover, with its concentrations controlled by the enzyme galactocerebrosidase (GALC), which degrades psychosine as part of galactolipid metabolism.

In Krabbe disease (globoid cell leukodystrophy), a deficiency of GALC leads to accumulation of psychosine in the brain and other tissues. Psychosine buildup is toxic to oligodendrocytes and Schwann cells, contributing to demyelination and the appearance of globoid cells. The lipid is also linked to inflammatory responses and can induce apoptotic pathways in neural cells. Because psychosine levels correlate with disease severity, measurement of psychosine in blood or cerebrospinal fluid is used as a biomarker and is employed in newborn screening programs in several regions.

Therapeutic approaches aim to reduce psychosine accumulation or restore GALC activity. These include hematopoietic stem cell transplantation in early infancy, gene therapy in experimental models, and substrate reduction strategies. Psychosine remains a focus of ongoing research for understanding Krabbe disease pathogenesis and for developing targeted therapies.

Synonyms: psychosine; galactosylsphingosine. It is a relatively small lipid that can influence membrane properties and cellular signaling at higher concentrations.