L-PGDS is upregulated in oligodendrocytes and a few neurons in the brain of murine models of various lysosomal storage diseases, such as Krabbe’s disease (Taniike et al., 1999; Mohri et al., 2006b), Tay–Sachs disease, Sandhoff disease, GM1 gangliosidosis and Niemann–Pick type C1 disease (Mohri et al., 2006a). The gene discussed is PTGDS; the disease is lysosomal storage disease.