Tay sachs disease

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.
CT

Macrocephaly and  diminished  attenuation  of  the entire  cerebral white matter  have been  reported  on  CT scans in patients with GM2 gangliosidose 5.

MRI

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
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Article information

rID: 21778
Tag: cases
Synonyms or Alternate Spellings:
  • GM2 gangliosidosis
  • Tay-sachs disease
  • Tay sachs disorder

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