What is Tay-Sachs Disease?
The classical form of TAY-SACHS disease (TSD) is a fatal, recessive genetic disorder in children that causes progressive destruction of the central nervous system.

When a person has Tay-Sachs disease, harmful quantities of a fatty substance called ganglioside GM2 accumulate in the nerve cells in the brain.

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 occur. The child becomes blind, deaf, and unable to swallow. Muscles begin to atrophy and paralysis sets in.

Tay-Sachs is named after Warren Tay (1843-1927) and Bernard Sachs (1858-1944). Warren Tay was a British ophthalmologist who in 1881 described a patient with a cherry-red spot on the retina of the eye. Bernard Sachs was a New York neurologist whose work several years later provided the first description of the cellular changes in Tay-Sachs disease. Sachs also recognized the familial nature of the disorder, and, by observing numerous cases, he noted that most babies with Tay-Sachs disease were of eastern European Jewish origin.

What causes Tay-Sachs?
Tay-Sachs disease is caused by the absence of a vital enzyme called hexosaminidase A (Hex-A). Without Hex-A, a fatty substance or lipid called GM2 ganglioside accumulates abnormally in cells, especially in the nerve cells of the brain. This ongoing accumulation causes progressive damage to the cells.

The destructive process begins in the fetus early in pregnancy, although the disease is not clinically apparent until the child is several months old. By the time a child with Tay-Sachs disease is three or four years old, the nervous system is so badly affected that life itself cannot be supported. Even with the best of care, all children with classical Tay-Sachs disease die early in childhood, usually by the age of five.

A baby with Tay-Sachs disease appears normal at birth and seems to develop normally until about six months of age. The first signs of TSD can vary and are evident at different ages in affected children. Initially, development slows, there is a loss of peripheral vision, and the child exhibits an abnormal startle response.

By about two years of age, most children experience recurrent seizures and diminishing mental function. The infant gradually regresses, losing skills one by one, and is eventually unable to crawl, turn over, sit, or reach out. Other symptoms include increasing loss of coordination, progressive inability to swallow and breathing difficulties. Eventually, the child becomes blind, mentally retarded, paralyzed, and non-responsive to his or her environment.

Symptoms
*Deafness
*Decreased eye contact, blindness
* Decreased muscle tone (loss of muscle strength)
*Delayed mental and social skills
* Dementia
*Increased startle reaction
* Irritability
* Listlessness
* Loss of motor skills
* Paralysis or loss of muscle function
* Seizures
* Slow growth

Signs and tests
If Tay-Sachs disease is suspected, the doctor will perform aphysical examination and take a family history. Additional tests may include:
*Enzyme analysis of blood or body tissue for hexosaminidase levels
* Eye examination (reveals a cherry-red spot in the macula)

Treatment
There is no treatment for Tay-Sachs disease itself, only ways to make the patient more comfortable.
Support Groups
The stress of illness may be eased by joining support groups whose members share common experiences and problems. See Tay-Sachs - support group.
Expectations (prognosis)
Children with this disease have symptoms that get worse over time. They usually die by age 4 or 5.

Complications
Symptoms appear during the first 3 to 10 months of life and progress to spasticity, seizures, and loss of all voluntary movements.
Calling your health care provider
Go to the emergency room or call the local emergency number (such as 911) if your child has a seizure of unknown cause, if the seizure is different from previous seizures, if the child has difficulty breathing, or if the seizure lasts longer than 2 - 3 minutes.
Call for an appointment with your health care provider if your child experiences a seizure lasting less than 2 - 3 minutes or has other noticeable behavioral changes.

Prevention
There is no known way to prevent this disorder. Genetic testing can detect if you are a carrier of the gene for this disorder. If you or your partner are from an at-risk population, it is recommended that you undergo testing before starting a family. Testing the amniotic fluid can diagnose Tay-Sachs disease in the womb.

Can Tay-Sachs be cured?
Currently, there is no cure or effective treatment for Tay-Sachs.

How is Tay-Sachs Disease transmitted?
Tay Sachs is transmitted through hereditary genes from parents to offspring. The Tay-Sachs genes are located on chromosome 15; these are the genes that code for the enzyme Hex-A. In order for a person to develop Tay-Sachs, they must receive defective Hex-A genes from both parents. If they receive a defective gene from only one parent, they will not develop the disease but will be a carrier of the disease.

What is the prognosis?
Most children with Tay-Sachs disease usually die before reaching age 5.

High occurrences of Tay-Sachs
Tay-Sachs occurs significantly high in persons of eastern European (Ashkenazi) Jewish descent. About one in every 27 Jews in the United States is a carrier of the Tay Sachs' gene.
 

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