Department of Biochemistry,
Rajah Muthiah Medical College,
The sphingolipids a complex range of
lipids in which fatty acids are linked via
amide bonds to a long-chain base or
They are also found in a few bacterial
Sphingomonas and Sphingobacterium.
Lysosomal storage diseases
The lysosomal storage diseases are
a rare class of neurometabolic
Metabolites of complex lipids
accumulate within neurons.
Mostly autosomal recessive fashion
For genetic counseling and for
monitoring future pregnancies.
They are characterized by a
progressive degenerative disease of
the nervous system, with blindness,
dementia, epilepsy, ataxia,
paralysis, and hyperreflexia.
A cherry-red spot at the macula and
optic atrophy are the most common
Ophthalmologic examination - an
important clue to the diagnosis.
Gangliosides are important constituents of
They are glycosphingolipids that contain
sialic acid in the oligosaccharide chain.
The metabolism of ganglioside involves the
removal of the terminal galactose to convert
GM1-ganglioside to GM2-ganglioside.
GM2-ganglioside is then hydrolyzed to GM3-
ganglioside by the removal of N-
D.Blue –GLU, L.Blue- sialic acid,
W-NAcGal, Y- Gal
They are neuronal lipid storage
disorders due to deficiencies of
certain lysosomal hydrolases.
Autosomal recessive inheritance
Progressive mental and motor
Due to the storage of GM1- or GM2-
ganglioside in neurons.
Lysosomal storage diseases are ultimately
There is no effective treatment.
Almost all the disorders diagnosed by
Leukocytes and cultured skin fibroblasts or
serum can be assayed for enzyme activity
Prenatal diagnosis is also possible.
Disease Enzyme Diagnostic Sample(s)
Tay-Sachs disease Hex A deficient Leukocyte serum
Sandhoff's disease Hex A and B deficient Leukocyte serum
AB variant Hex A, B normal GM2loading studies in
B1variant Hex A deficient with sulfated
Partial Hex A deficiency Leukocyte serum
ß-Galactosidase deficient Leukocyte fibroblasts
Type A, infantile Sphingomyelinase deficient Leukocyte fibroblasts
Type B Sphingomyelinase deficient Leukocyte fibroblasts
Ceramidase Leukocyte fibroblasts
Type 1 Sialidase deficient Fresh fibroblasts
Type 2 Sialidase and ß-galactosidase