B IO C H E M IS T R Y PE A R L S
Sphingolipids are a class of lipids found in biological membranes in
which the backbone of the lipid molecule is sphingosine, an 18-
carbon amino alcohol.
Sphingolipids are constantly being turned over in the lysosomes of
cells by specific hydrolytic enzymes that remove the sugars in a
stepwise fashion. Defects in these enzymes can result in accumu-
lation of undegraded sphingolipids.
This disease results from a deficiency in the enzyme hexosaminidase
A (P-N-acetylhexosaminidase). The deficiency in hexosaminidase
A leads to the accumulation of ganglioside GM2 in the nerve cells
of the brain.
Other lysosomal storage disorders include GM1 gangliosidoses, GM2
gangliosidoses, Gaucher disease, Niemann-Pick disease, Fabry
disease, fucosidosis, Schindler disease, metachromatic leukodys-
trophy, Krabbe disease, multiple sulfatase deficiency, Farber dis-
ease, and Wolman disease.
Berg JM, Tymoczko JL, Stryer L. Biochemistry, 5th ed. New York: Freeman,
Devlin TM, ed. Textbook of Biochemistry with Clinical Correlations, 5th ed.
New York: Wiley-Liss, 2002:762-5.