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Tay-Sachs disease (GM2 gangliosidosis, type 1 or infantile cerebral sphingolipidosis, Infantile amaurotic familial idiocy)
Epidemiology:
-> occurs mainly among Jews of Eastern European origin
Pathology:
1) hexosaminidase A deficiency
2) abnormal metabolism of GM2 gangliosides
3) cerebral atrophy
Genetics:
1) autosomal recessive
2) HEXA gene mutations are the cause of Tay-Sachs disease
3) defects in PSAP saposin D region are a cause of Tay-Sachs disease variant
4) defects in GM2A are the cause of Tay-sachs disease AB variant
Clinical manifestations:
1) Early manifestations
- insidious onset in apparently healthy infants
- decreased motor activity
- flaccidity
- apathy
- inattentiveness
2) Late manifestations
- spasticity
- clonus
- positive Babinski sign
- convulsions
- blindness
- mental retardation
- cherry red spot on macula
- death between 1st & 4th year of life
Laboratory:
- PSAP genotyping
- HEXA gene mutation
- HEXA gene deletion
- see ARUP consult [2]
Related
beta N-acetyl hexosaminidase alpha chain (hexosaminidase-A, HEXA)
chromosomal aberration
GM2 ganglioside
PSAP genotyping
General
GM2 gangliosidosis
Properties
ACCUMULATION: GM2 ganglioside
DEFICIENCY: beta N-acetyl hexosaminidase alpha chain
Database Correlations
OMIM 272800
References
- Textbook of Biochemistry with Clinical Correlations,
3rd ed., TM Devlin (ed), Wiley-Liss, NY 1992 pg 459
- ARUP Consult: Tay-Sachs Disease Testing
https://arupconsult.com/ati/tay-sachs-disease-testing
- ARUP Consult: Jewish Genetic Disease
The Physician's Guide to Laboratory Test Selection & Interpretation
- Ashkenazi Jewish Genetic Diseases Carrier Screening Algorithm
https://arupconsult.com/algorithm/jewish-genetic-diseases-carrier-screening-algorithm
- Ashkenazi Jewish Genetic Diseases Panel
https://arupconsult.com/ati/ashkenazi-jewish-genetic-diseases-panel
- NINDS Tay-Sachs Disease Information Page
https://www.ninds.nih.gov/Disorders/All-Disorders/Tay-Sachs-Disease-Information-Page
- Learning About Tay-Sachs Disease
http://www.genome.gov/page.cfm?pageID=10001220