Figure 29.5 Tay–Sachs disease results from the inability to degrade a ganglioside. A particular ganglioside, G_M2, accumulates in Tay–Sachs patients because a key step in its degradation, conversion into ganglioside G_M3, cannot take place, because of insufficient β-N-acetylhexosaminidase. Abbreviations: GalNAc, N-acetylgalactosamine; NAN, N-acetylneuraminate; Gal, galactose; Glc, glucose.