Tay-Sachs disease is a hereditary neurodegenerative disorder resulting from excess storage of GM2 ganglioside within the lysosomes of cells.
The incidence of the disease is estimated to be 1 in 3600 in Ashkenazi Jews with carrier frequency of 1 in 30 and 1 in 360,000 in other population with carrier frequency of 1 in 300. Tay-Sachs disease is the most frequently occurring sphingolipidoses.
In Tay-Sachs disease, a genetic mutation known as the HEXA mutation results in the body not producing an enzyme called Hexosaminidase-A (Hex-A). Without this enzyme, a fatty substance called ganglioside builds up in the cells of the nervous system, causing them to stop working normally 3-7.
At 3 to 6 months
- decreased eye contact.
- twitchy eyes (myoclonic jerks).
- difficulty focusing on objects.
- excessive startling by sharp but not necessarily loud noises.
At 6 to 10 months
- limp and floppy muscles (hypotonia).
- decreased alertness and playfulness.
- difficulty sitting up or rolling over
- loss of motor skills.
- decreased hearing and eventual deafness.
- gradual loss of vision.
- an abnormal increase in head size (macrocephaly).
10 months and older
As a child with Tay-Sachs grows older, he or she may become blind, mentally retarded, paralyzed, and unresponsive to the environment. The child also may have seizures, difficulty swallowing, and difficulty breathing. Children with Tay-Sachs disease rarely live beyond 4 or 5 years of age 1-7.
Screening for Tay-Sachs disease is recommended for people in high-risk groups. This includes people of Ashkenazi Jewish descent and anyone with a history of the condition in their family.
- preconception screening – where potential parents are able to check whether they carry the HEXA mutation before starting a family
- antenatal screening - where a fetus is checked to see whether two copies of the HEXA mutation have been inherited, which would cause Tay-Sachs disease to develop.
Macrocephaly and diminished attenuation of the entire cerebral white matter have been reported on CT scans in patients with GM2 gangliosidose 5.
MR is apparently superior to CT in clearly delineating lesions of this disease. With MRI, deep white matter demyelination may be prominent; thalami may show changes consistent with calcification. No abnormal contrast enhancement is described 1-5.
Because there is no cure for Tay-Sachs disease, the goal of treatment is to make the patient comfortable.
Inborn errors of metabolism
- disorders of carbohydrate metabolism
- disorders of amino acid metabolism
disorders of the urea cycle
- carbamoyl phosphate synthetase I deficiency
- ornithine transcarbamylase deficiency (OTCD)
- disorders of organic acid metabolism
- disorders of fatty acid oxidation and mitochondrial metabolism
- disorders of porphyrin metabolism
- disorders of purine or pyrimidine metabolism
- disorders of steroid metabolism
- disorders of mitochondrial function
- disorders of peroxisomal function
lysosomal storage disorders
- activator Deficiency/GM2 Gangliosidosis
- cholesteryl ester storage disease
- chronic hexosaminidase A Deficiency
- Danon disease
- Fabry disease
- Farber disease
- Gaucher disease
- GM1 gangliosidosis
- I-Cell disease/Mucolipidosis II
- infantile free sialic acid storage disease
- juvenile hexosaminidase A deficiency
- Krabbe disease
- lysosomal acid lipase deficiency
- metachromatic Leukodystrophy
- multiple sulfatase deficiency
- Niemann-Pick disease
- meuronal ceroid lipofuscinoses
- CLN6 disease
- Finnish Variant Late Infantile CLN5
- Jansky-Bielschowsky disease
- Kufs disease
- northern epilepsy
- Santavuori-Haltia disease
- Pompe disease
- Sandhoff disease
- Schindler disease
- Salla disease
- Tay-Sachs disease
- Wolman disease
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