TANGIER DISEASE Raquel Calvete

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TANGIER DISEASERaquel Calvete

• What is TD, and what causes it?
• What does TD tell us about cholesterol and
  atherosclerosis?

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What is it named after?
Taken from http//dopas.ch/captaindom/2003_10_Fli
ghtsToTangier/2003_10_FlightsToTangier_001.html
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Normally
Cholesterol is successfully transported out of
cells and processed

• ABC1 is present to aid cholesterol out of the
  cell
• Cholesterol then binds with Apo-A1 lipoprotein
  outside the cell forming HDL
• HDL picks up additional lipids from LDL and VLDL
  lipoproteins and transfers the cholesterol to the
  liver, where it is processed

Image taken from http//www.ncbi.nlm.nih.gov/book
s/bv.fcgi?callbv.View..ShowSectionridgnd.sectio
n.237
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In Tangier Syndrome

• Cholesterol is forced to accumulate within the
  cell, since there is a mutation present in ABC1

Image taken from http//www.ncbi.nlm.nih.gov/book
s/bv.fcgi?callbv.View..ShowSectionridgnd.sectio
n.237
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TD is a genetic disorder

• ABC1 gene is located on chromosome 9q31
• It codes for an mRNA that is 6,783 base pairs and
  a protein that is 2,261 amino acids in size
• The protein synthesised is a transmembrane
  protein with 12 transmembrane domains

Image taken from http//www.ncbi.nlm.nih.gov/dise
ase/chr9-12.html
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CHARACTERISTICS OF TANGIER DISEASE

• Hypertrophic orange-colour tonsils
• Very low levels of HDL in the plasma
• An enlarged liver and spleen
• Premature coronary artery disease

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How does it link to atherosclerosis

• This disease leads to increased cholesterol
  esters in the tonsils, spleen, liver, skin and
  lymph nodes
• The discovery of this cholesterol gene has lead
  to a better understanding of the inverse
  relationship between HDL and coronary heart
  disease
• Since it leads to atherosclerosis, it clearly
  shows that cholesterol is an important factor in
  heart disease
• It is a rare disease but it demonstrates that we
  should be aware of our cholesterol levels