Tay-Sachs
Disease
(GM2 Gangliosidosis: Hexosaminidase
alpha-subunit Deficiency)
Epidemiology:
Common sites:
Gross features:
Histologic features:
- accumulation of GM2
ganglioside in many tissues
- nervous system
- heart
- liver
- spleen
- nervous system:
- central and
autonomic nervous systems and retina involved
- neurons
ballooned with cytoplasmic vacuoles
- markedly
distended lysosomes filled with gangliosides
- over time:
- progressive
destruction of neurons
- proliferation
of microglia
- accumulation of
complex lipids in phagocytes
Immunophenotype:
Marker:
|
Sensitivity:
|
Specificity:
|
Oil red O
|
|
|
Sudan black B
|
|
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Molecular features:
Other features:
- EM – cytoplasmic inclusions, including whorled
configurations composed of onion-skin layers of membranes
- autosomal recessive inheritance
- inability to catabolize GM2 gangliosides
- mutation in
alpha subunit locus on chromosome 15 for gangliosidase
enzyme
- cherry red spot in
macula on retinal examination (accentuation of normal macular colour with surrounding ganglioside-swollen
neurons)
References: