ST3GAL5 and multiple sclerosis: For example, mutations in the ST3Gal5 gene that encodes monosialoganglioside GM3 synthase have been linked to infant onset epilepsy, while mutations in the ST3Gal5 and B4GalNT1 genes, which encode GM2 synthase, increase the risk of developing multiple sclerosis (Schengrund, 2015).