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Lysosomal sphingolipid catabolism and enzyme deficiencies causing storage diseases

A schematic of the various sphingolipid metabolic pathways shows the enzymes whose deficiency leads to several diseases. Note that each enzyme is assisted by one or more saposins (Saps): (1) GM2A assists both β-gal and β-hexosaminidase; (2) SapB assists sialidase, α-GAL, GALC, and β-gal; (3) SapC assists GALC, β-gal, GCase, acid ceramidase, and GALC; (4) SapD assists acid ceramidase.

Abbreviations: Cer, ceramide; DiGalCer, digalactosylceramide; Gal, galactose; GalCer, galactosylceramide; GalNAc, N-acetylgalactosamine; Gb3, globotriaosylceramide; Gb4, globotetraosylceramide; Glc, glucose; GlcCer, glucosylceramide; LacCer, lactosylceramide; Neu5Ac, N-acetylneuraminic acid; SM, sphingomyelin; SM4, 3-O-sulfogalactosylceramide; Sph, sphingosine.

(Source: Abed Rabbo M, Khodour Y, Kaguni LS, Stiban J. Sphingolipid lysosomal storage diseases: from bench to bedside. Lipids Health Dis 2021;20[1]:44. Creative Commons Attribution 4.0 International License,

Associated Disorders

  • Adult globoid cell leukodystrophy
  • Diffuse brain-sclerosis
  • Diffuse gliosis
  • Early infantile globoid cell leukodystrophy
  • Juvenile globoid cell leukodystrophy
  • Late infantile globoid cell leukodystrophy
  • Leukodystrophy