A child has a 25% chance of developing the Tay-Sachs disease, if both parents carry the defective Tay-Sachs gene on the chromosome 15. The following HealthHearty write-up provides information on this fatal genetic disorder.
Tay-Sachs disease is an autosomal recessive genetic disorder that is characterized by progressive mental and physical deterioration. It is one of the severe forms of the deficiency of Hexosaminidase A, which is a protein that is required for breaking down gangliosides, a chemical found in nerve tissue. The lack of Hexosaminidase A leads to the buildup of ganglioside GM2 in the brain, which in turn leads to this disease.
For a child to develop this condition, one copy of the defective gene needs to be passed on from each parent. However, if the child inherits one defective gene and one normal gene from the parents, he/she will only be the carrier of the disease. This disease is more common in Ashkenazi Jews.
This disease is classified into infantile, juvenile, and adult forms, on the basis of the onset of the symptoms.
Infantile Onset: The symptoms of Tay-Sachs disease start making an appearance when the child is around 3 to 6 months of age. The symptoms include:
- Slow growth and development
- Weak muscles
- Loss of motor skills like sitting, crawling, and turning around in sleep
- Increased startle reflex to noise
- Loss of vision and hearing
- Inability to swallow
- Mental retardation
These children show an eye abnormality, which is called the cherry-red spot. This spot is visible during eye examination and is known to be a characteristic of this disease.
Juvenile Onset: This is a very rare form. The symptoms could appear in the children in the age group of 2 to 10 years. The symptoms include:
- Cognitive disabilities
- Loss of motor skills
- Dysarthria (speech difficulty)
The progression of the disease is slower in comparison to infantile onset.
Adult Onset: This condition is not as fatal as the other two forms. The symptoms appear when the person is in late 20s or early 30s. The symptoms include slurred speech, muscle weakness, tremors, unsteady gait, and progressive neurological deterioration. Some people may suffer from psychosis.
Diagnosis and Treatment
The disease is diagnosed by measuring the hexosaminidase A levels in body. An eye examination helps the doctor spot the characteristic cherry-red spot at the back of the eyes. There is no cure for this disease. The treatment is aimed at controlling the symptoms.
A person can undergo genetic testing to find out if he/she is a carrier of the HEX-A gene. Genetic counseling will help you get answers to doubts that you may have regarding this genetic disorder.
Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.