Tay Sachs Disease

Overview of Tay-Sachs Disease

• Tay-Sachs disease is a rare genetic disorder passed from parents to child.
• It's caused by the absence of an enzyme that helps break down fatty substances called gangliosides.
• These gangliosides build up to toxic levels in the brain and spinal cord, affecting the function of nerve cells.

Genetic Basis

• Tay-Sachs is an autosomal recessive disease caused by mutations in both alleles of the HEXA gene on chromosome 15.
• The HEXA gene codes for the alpha subunit of the enzyme β-hexosaminidase A, which breaks down GM2 ganglioside.
• Mutations in the HEXA gene can result in reduced or absent activity of the Hex-A enzyme, leading to the accumulation of GM2 ganglioside within nerve cells.

Types of Tay-Sachs Disease

• Infantile Tay-Sachs: the most common form, develops soon after birth, and causes death early in childhood; often passes away before the age of 5.
• Juvenile Tay-Sachs: affects children ages 2 and older, progresses more slowly than the infantile form, and children don't live beyond their mid-teens.
• Late-onset Tay-Sachs: a rare and milder form, starts between puberty and the mid-30s, and some people may live a normal lifespan.

Symptoms and Causes

• Symptoms vary in severity and type of Tay-Sachs disease and may become more pronounced as the disease progresses.
• Common symptoms include:
  • Developmental delay
  • Muscle weakness
  • Loss of motor skills
  • Increased startle response
  • Hypotonia
  • Seizures
  • Vision and hearing loss
  • Cherry-red spot on the retina

Diagnosis

• Diagnosis involves:
  • HEX-A blood test to check the levels of hexosaminidase enzyme in the blood.
  • Genetic testing to examine the HEXA gene for changes that indicate Tay-Sachs disease.
  • Eye exam to detect a cherry-red spot in the back of the eyes.

Treatment and Management

• There is no cure for Tay-Sachs disease, but treatment is supportive of symptoms.
• Medications can be prescribed to manage seizures, and other treatment measures include providing proper nutrition and hydration.
• Respiratory care, including chest physiotherapy and medications to reduce saliva production, can help manage respiratory problems.
• Assistive feeding devices, such as feeding tubes, may be necessary to prevent respiratory problems.

Prevention and Genetic Counseling

• Prevention of Tay-Sachs disease involves genetic counseling and testing for carriers of the Tay-Sachs gene.
• Genetic testing can help identify carriers and provide information for family planning decisions.
• Genetic counseling is important for individuals who are carriers of the Tay-Sachs gene to understand the risks and options available.

Oral and Dental Manifestations

• Dental caries (tooth decay) and periodontal disease (gum disease) can be concerns for individuals with Tay-Sachs disease.
• Special care, including gentle and careful handling, is necessary for dental check-ups and treatments.
• Prevention measures, such as regular cleanings and fluoride treatments, can help prevent tooth problems.
• Dentists need to work together with doctors to plan the best care for patients with Tay-Sachs disease.

A rare genetic disorder caused by the absence of an enzyme, leading to toxic build-up in the brain and spinal cord. Symptoms appear around 3-6 months of age.