Fig. 3.

Catabolism of complex SP and diseases associated with deficiencies in these enzymes and/or activator proteins (Kolter and Sandhoff 2006). The color symbols and scheme for these compounds are the same as shown in Fig. 1 and 2. The SP turnover-related diseases are indicated by number with: (1) GM1-gangliosidosis; (2) Tay-Sachs disease/Sandhoff AB variant; (3) Sandhoff disease; (4) Fabry disease; (5) Sialidosis; (6) Gaucher disease; (7) metachromatic leukodystrophy; (8) globoid cell leukodystrophy/Krabbe disease; (9) Niemann Pick disease; (10) Farber disease. The abbreviations are as follows: Choline-P phosphatidylcholines; Et-P phosphatidylethanolamine; Glc glucose; GlcNAc N-acetylglucosamine; Gal galactose; GalNAc N-acetylgalactosamine; and NeuAc, N-acetylneuraminic acid