Several other mouse models of the lysosomal storage disease (Tay-Sachs, GM1 gangliosidosis, Fabry, NCP1) also show a reduced number of type I NKT cells, not due to defective CD1d presentation or lack of APCs, but due to impaired loading of lipid antigen on to the CD1d molecule (82). The gene discussed is CD1D; the disease is GM1 gangliosidosis.