HEXB and gangliosidosis: GM2-Gangliosidosis, including Thy-Sachs disease (OMIM #272800) and Sandhoff disease (OMIM #268800), are caused by mutations in the HEXA and HEXB genes, which encode the α and β subunits of the enzyme lysosomal β-hexosaminidase, respectively, leading to Accumulation of GM2-Gangliosidosis(1).