What Is Tay-Sachs Disease?
Tay-Sachs disease is a rare, inherited disorder that causes progressive destruction of nerve cells located in the brain and spinal cord.
How Common Is Tay-Sachs Disease?
Tay-Sachs disease is very rare in the general population. The genetic mutations that cause the disease are more common in people of Ashkenazi (eastern and central European) Jewish heritage than in those of other backgrounds. Approximately 1 in every 27 Jews in the United States is a carrier of the Tay-Sachs disease gene.
The genetic mutations that cause Tay-Sachs disease are also more common in:
- Certain French-Canadian communities of Quebec
- Some Amish groups
- The Cajun community of Louisiana.
Causes of Tay-Sachs Disease
Tay-Sachs disease is a condition that is passed from parent to child through a defect (mutation) of the HEXA gene located on chromosome number 15. The HEXA gene is responsible for making a vital enzyme called hexosaminidase-A (HEXA). Without HEXA, a fatty substance (lipid) called GM2 ganglioside accumulates abnormally in cells, especially in the nerve cells of the brain.
Is Tay-Sachs Disease Inherited?
Tay-Sachs disease is an autosomal recessive condition, which means that both parents must have this defective gene in order for a child to inherit Tay-Sachs disease.
When both parents are carriers (meaning that one HEXA gene is normal and one is defective but they have no symptoms), each child has a 25 percent chance of having Tay-Sachs disease and a 50 percent chance of being a carrier.
Symptoms of Tay-Sachs Disease
Infants with Tay-Sachs disease appear to develop normally for the first few months of life. Then, as nerve cells become distended with fatty material, a relentless deterioration of mental and physical abilities occurs. The child becomes blind, deaf, and unable to swallow. Muscles begin to atrophy, and paralysis sets in.
A much rarer form of the disorder occurs in patients in their 20s and early 30s, and is characterized by an unsteady gait and progressive neurological deterioration.
People with Tay-Sachs also have "cherry-red" spots in their eyes.
Diagnosing Tay-Sachs Disease
When
diagnosing Tay-Sachs disease, the doctor will ask a number of questions about symptoms and family history, perform a physical exam, and recommend certain tests, including a blood test.
Patients and carriers of Tay-Sachs disease can be identified by a simple blood test that measures HEXA activity. Prenatal diagnosis of Tay-Sachs disease is available if desired.
Treatment for Tay-Sachs Disease
There is no Tay-Sachs cure or way of slowing down the progression of Tay-Sachs disease. Therefore,
treatment for Tay-Sachs disease focuses on controlling the symptoms. Some of these treatments for Tay-Sachs disease may include:
- Medications
- Techniques to keep the airway open.
Treatment also focuses on lifestyle and care issues, including:
- Feeding
- Proper nutrition and hydration.
Prognosis for Tay-Sachs Disease
Even with the best of care, children with Tay-Sachs disease usually die by age 4 from recurring infection. People with adult-onset Tay-Sachs disease can live full adult lives, although most become wheelchair-bound.
History of Tay-Sachs Disease
Tay-Sachs disease was named after two physicians. The first was the British physician, Warren Tay, who first described the red spot on the retina of the eye in 1881. The second was the American physician, Bernard Sachs, who described the changes that occur within cells and noted an increased prevalence in the eastern and central European Jewish (Ashkenazi) population.
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