Tay – Sachs disease
Warren Tay
Bernard Sachs
What is Tay – sachs disease?
• A rare inherited genetic disorder that progressively
destroys nerve cells (neurons) in the ...
What is Tay – sachs disease?
What is Tay – sachs disease?
•People with Tay-Sachs don't
have the DNA instructions to
make Hex-A correctly: usually
they ...
What is tay – sachs disease?
• This condition is inherited in an autosomal
recessive pattern, which means both copies of
t...
• Mutations in the HEXA gene disrupt the activity of
beta-hexosaminidase A (prevents the enzyme from
breaking down GM2 gan...
• As a result, this substance accumulates to toxic
levels, particularly in neurons in the brain and spinal
cord.
• Progres...
The cherry red spot
The cherry red spot
• One of the signs of Tay-Sachs is the presence of a cherry-red
spot.
• The center of the fovea appear...
Primary symptoms:
• Rapidly declining development
• Weakening of muscles
• Loss of motor skills
Followed by:
• They deve...
• In children, the destructive process begins in the
fetus early in pregnancy.
• However, a baby with Tay-Sachs disease ap...
• A much rarer form of Tay-Sachs, Late-Onset Tay-Sachs
disease, affects adults and causes neurological and
intellectual im...
Tay – sachs disease
Tay – sachs disease
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Tay – sachs disease

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Tay – sachs disease

  1. 1. Tay – Sachs disease
  2. 2. Warren Tay Bernard Sachs
  3. 3. What is Tay – sachs disease? • A rare inherited genetic disorder that progressively destroys nerve cells (neurons) in the brain and spinal cord, most commonly occurring in children. • A disease where your lysosomes (use enzymes to break down extra stuff in your body and recycle it) aren't working right due to the absence of the enzyme hexosaminidase 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.
  4. 4. What is Tay – sachs disease?
  5. 5. What is Tay – sachs disease? •People with Tay-Sachs don't have the DNA instructions to make Hex-A correctly: usually they make the Hex-A, but something is wrong with the hooks that the cell uses to move the Hex-A around inside the cell. •Tay-Sachs disease results from defects in a gene on chromosome 15 that codes for production of the enzyme Hex-A. We all have two copies of this gene.
  6. 6. What is tay – sachs disease? • This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. • The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. • It's a disease you get in your DNA from your parents, and both your mother and your father have to have the disease in their DNA in order for you to get it. • It is not catching.
  7. 7. • Mutations in the HEXA gene disrupt the activity of beta-hexosaminidase A (prevents the enzyme from breaking down GM2 ganglioside). • The HEXA gene provides instructions for making part of an enzyme called beta-hexosaminidase A, which plays a critical role in the brain and spinal cord. • This enzyme is located in lysosomes, which are structures in cells that break down toxic substances and act as recycling centers. • Within lysosomes, beta-hexosaminidase A helps break down a fatty substance called GM2 ganglioside.
  8. 8. • As a result, this substance accumulates to toxic levels, particularly in neurons in the brain and spinal cord. • Progressive damage caused by the buildup of GM2 ganglioside leads to the destruction of these neurons, which causes the signs and symptoms of Tay-Sachs disease. • Because Tay-Sachs disease impairs the function of a lysosomal enzyme and involves the buildup of GM2 ganglioside, this condition is sometimes referred to as a lysosomal storage disorder or a GM2- gangliosidosis.
  9. 9. The cherry red spot
  10. 10. The cherry red spot • One of the signs of Tay-Sachs is the presence of a cherry-red spot. • The center of the fovea appears bright red because it is surrounded by a milky halo. • This halo represents loss of retinal transparency which comes from a pile up of ganglioside in ganglion cells. • The ganglioside accumulates because its catabolic enzyme (hexosaminidase A) is missing. Remember that there are no ganglion cells in the center of the fovea, so that the underlying choroid transmits its red color. • A similar metabolic cherry-red spot occurs in other lysosomal enzyme deficiences such as generalized gangliosidosis (GM 1), Sandhoff's, Gaucher's, mucolipidosis Types 1 and 2, Niemann- Pick Type A, and multiple sulfatase deficiency. Vision is usually subnormal because the ganglion cells are not working properly.
  11. 11. Primary symptoms: • Rapidly declining development • Weakening of muscles • Loss of motor skills Followed by: • They develop an exaggerated startle reaction to loud noises • Blindness • Deafness • Inability to swallow or chew • Mental retardation • Paralysis • Dementia Note: Leads to death at the age of 4 – 5 years old.
  12. 12. • In children, the destructive process begins in the fetus early in pregnancy. • However, a baby with Tay-Sachs disease appears normal until about six months of age when its development slows. • By about two years of age, most children experience recurrent seizures and diminishing mental function. • The infant gradually regresses, and is eventually unable to crawl, turn over, sit or reach out. Eventually, the child becomes blind, cognitively impaired, paralyzed and non-responsive. • By the time a child with Tay-Sachs is three or four years old, the nervous system is so badly affected that death usually results by age five.
  13. 13. • A much rarer form of Tay-Sachs, Late-Onset Tay-Sachs disease, affects adults and causes neurological and intellectual impairment. • The disease has not been extensively described. • As for the childhood form of Tay-Sachs, there is no cure. • Treatment involves managing the symptoms of the disease.

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