GlcCer(d18:1/18:0) is a glycosphingolipid (ceramide and oligosaccharide)or oligoglycosylceramide with one or more sialic acids (i.e. n-acetylneuraminic acid) linked on the sugar chain. It is a component the cell plasma membrane which modulates cell signal transduction events. Gangliosides have been found to be highly important in immunology. Ganglioside GL1a carries a net-negative charge at pH 7.0 and is acidic. Gangliosides can amount to 6% of the weight of lipids from brain, but they are found at low levels in all animal tissues.Cerebrosides are glycosphingolipids. There are four types of glycosphingolipids, the cerebrosides, sulfatides, globosides and gangliosides. Cerebrosides have a single sugar group linked to ceramide. The most common are galactocerebrosides (containing galactose), the least common are glucocerebrosides (containing glucose). Galactocerebrosides are found predominantly in neuronal cell membranes. In contrast glucocerebrosides are not normally found in membranes. Instead, they are typically intermediates in the synthesis or degradation of more complex glycosphingolipids. Galactocerebrosides are synthesized from ceramide and UDP-galactose. Excess lysosomal accumulation of glucocerebrosides is found in Gaucher disease.