Tay-Sachs Disease - Causes, Symptoms, and Treatment

What Is Tay-Sachs Disease?

Tay-Sachs disease is a hereditary condition affecting the neuron cells of the central and peripheral nervous system (brain and spinal cord). This disease is passed on to future generations. Children suffering from Tay-Sachs disease are characterized by the absence of a specific enzyme, hexosaminidase A, that catabolizes fatty substances. The lack of hexosaminidase A causes the fatty substances to collect. The accumulation of these fatty substances, called gangliosides, is responsible for manifesting symptoms of Tay-Sachs disease, such as poor muscle strength.

Tay-Sachs disorder worsens with time. A defect occurs in a pair of genes that are inherited from parents. A progressive, debilitating disease where children born with the particular disease symptoms usually die by four years. This occurs due to the severe complications of pneumonia. There is no treatment for the disorder. The doctor tries to manage the patient and keep him comfortable. Genetic counseling and genetic testing are highly recommended for high-risk group individuals or pregnant women.

What Is the Epidemiology of Tay-Sachs Disease in Children?

For the general population that does not fall into the high-risk group, about 1 in every 310 people carry the defective gene for Tay-Sachs. People originating from Ashkenazi Jewish descent are at a higher risk of acquiring this disease. Approximately 4 in every 30 people carry the defective gene. About 1 in 3500 infants are affected.

The variant gene is present in specific populations only. So, the predisposing factors for Tay-Sachs disease include the populations of

• Jewish communities (Ashkenazi Jews) in Eastern and Central Europe.

• French Canadian people.

• People of Irish ancestry.

• The Amish community in Pennsylvania.

A blood test is usually recommended to identify the risk carriers of the variant gene. Genetic counseling is also preferred after the test.

What Are the Causes of Tay-Sachs Disease in Children?

1. Hereditary Causes - Tay-Sachs disease is a hereditary condition that is passed down the future generations. It occurs when the defective HEXA gene is inherited by the child from both parents.

2. Lack of Enzyme Beta-Hexosaminidase A -This enzyme is responsible for breaking down gangliosides (fatty substances). The excessive buildup of these harmful gangliosides leads to the destruction of the neural cells present in the brain and spinal cord.

3. Age of Onset - This is an important factor that determines the course of the disease and the amount of enzyme that can be produced.

What Are the Symptoms of Tay-Sachs Disease in Children?

There are four forms of Tay-Sachs disease: infantile, juvenile, chronic, and late-onset.

Infantile Form:

• It is the most frequent form that presents in a severe form in infants.

• The symptoms begin to appear in newborns at the age of three to six months.

• The survival rate of the child is poor.

• The clinical signs and symptoms can include

  • Exaggerated sudden shock response on hearing loud noises by the baby.

  • Spots in the eyes that are cherry-red in color.

  • Lack of motor skills. The baby is not able to crawl, turn over, or sit up on his own.

  • Progressive weakening of the muscles in children leads to paralysis.

  • Epileptic fits and seizures.

  • Difficulty in moving.

  • Loss of vision in children, sometimes leading to blindness.

  • Hearing loss.

  • Difficulty swallowing food.

  • Poor cognitive skills.

  • Poor mental development.

  • Progressive macrocephaly (large head size).

Juvenile Form:

• This form is relatively less common.

• The survival age may extend up to the teenage years.

• Social behavioral problems.

• Gradual loss of motor skills.

• Loss of movement control.

• Frequent infections of the respiratory tract.

• Blindness.

• Difficulty speaking.

• Delayed responses.

• Poor mental growth.

• Seizures (fits).

Late Childhood Onset (Adult Form):

• It is an uncommon and relatively less severe form than the other two.

• The signs and symptoms begin in late childhood to even adulthood.

• This form usually does not affect life expectancy.

• Muscle atonia.

• Lack of coordination.

• Clumsy teens.

• Frequent tremors.

• Spasms in the muscles.

• Difficulty speaking and swallowing.

• Difficulty walking.

• Neurological disorders.

• Loss of mental abilities.

Chronic Tay-Sachs:

• In this form, the children usually develop symptoms before the age of ten years.

• This is a neurodegenerative form of the disease.

• Seizures start at an early age.

• Lack of responsiveness.

• Low muscle tone.

• Myoclonic jerks (sudden muscular contractions while falling asleep).

How Is Tay-Sachs Disease in Children Diagnosed?

• Blood Test: Healthcare professionals suggest a blood test to diagnose Tay-Sachs disease in children. The level of hexosaminidase A enzyme in the child’s body is identified. It is generally observed that a child suffering from the classic form of Tay-Sachs disease shows a complete absence of the enzyme. Children with other less severe forms of the disease have reduced enzyme levels.

• Optical Examination: The doctor may also perform an eye examination to diagnose the classic cherry-red spots in the child’s eye.

• Prenatal Testing: This test can be done during pregnancy by removing a piece of the placenta or extracting a sample of amniotic fluid to diagnose the disease in the fetus.

How Is Tay-Sachs Disease Treated?

There is no definitive treatment for Tay-Sachs disease. The treatment aims at minimizing the symptoms of the affected children by imparting them some comfort and relief. The treatment measures include:

• Medications to control seizures.

• A balanced diet with nutritional supplements should be provided.

• Proper hydration of the child is crucial.

• Proper speech and language therapy should be given to the child.

• Physiotherapy is needed to keep the joints mobile and flexible.

• Respiratory care should be provided to prevent the occurrence of infections.

• Genetic counseling for the family members and relatives of the affected child should be carried out.

What Is the Prognosis for Children With Tay-Sachs Disease?

Usually, most forms of Tay-Sachs disease are life-threatening. The prognosis of the disease in the infantile form is very poor, with a survival rate of not more than four years. In the late childhood onset form, life expectancy is not much affected.

Conclusion:

Tay-Sachs disease is a rare neurodegenerative condition in children. It leads to progressive damage of the nerve cells in the brain and spinal cord, leading to poor muscle atonia and lack of coordination. The disease cannot be prevented since it is hereditary. However, the pregnancy should be planned after prenatal counseling and testing among parents who are at a higher risk. No definitive cure for the disease condition is available. More research is required in this field.