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Cystic Fibrosis (CF)• Causes  – Several different alleles of a key gene coding for a    transmembrane protein that transpo...
ALBIO9700/2006JK
ALBIO9700/2006JK
• Effects of CF  – Reduced chloride transport through cell membranes    leads to production of thick, sticky mucus that af...
ALBIO9700/2006JK
Progress towards treating Cystic   Fibrosis with gene technology• Current treatments deal with the symptoms rather than  t...
• A vector must be used to deliver the DNA  containing the functional CFTR gene into the  lung cells  – Viral delivery sys...
ALBIO9700/2006JK
ALBIO9700/2006JK
• There is not yet a successful example of  treatment of CF by gene therapy because:  – Current viral vectors have been fo...
• http://www.machinegraphics.com/animation/an• http://presenter.multicastmedia.com/links/CFF• http://learn.genetics.utah.e...
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05 Cystic Fibrosis

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05 Cystic Fibrosis

  1. 1. Cystic Fibrosis (CF)• Causes – Several different alleles of a key gene coding for a transmembrane protein that transports chloride ions through cell surface membranes (cystic fibrosis transmembrane regulator, CFTR) – Inheritance is autosomal (NOT sex-linked) and recessive – located on chromosome 7 – CF alleles originate by mutation of the CFTR protein, but can be inherited through many generations – Individuals with a single copy of such an allele are heterozygous and do not have the condition (10 million carriers worldwide) – To have CF, it is necessary to be homozygous for CF alleles ALBIO9700/2006JK
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  4. 4. • Effects of CF – Reduced chloride transport through cell membranes leads to production of thick, sticky mucus that affects lungs, pancreas and reproductive organs – The mucus remains in the lungs leading to wheezing and repeated infections (removed by physiotherapy) – Mucus may block pancreatic duct, compromising digestion and nutrition and also causing build-up of protease in the pancreas, damaging the pancreatic tissue – Mucus may block sperm ducts (male infertility) and may slow the progress of eggs and sperm through the oviducts (reducing female fertility) ALBIO9700/2006JK
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  6. 6. Progress towards treating Cystic Fibrosis with gene technology• Current treatments deal with the symptoms rather than the causes• Research continues to try and develop techniques for adding functional copies of the CFTR gene to the cells of people with CF• It is thought that if even a proportion of lung cells could be given a working copy of the gene, this would thin the mucus sufficiently to allow the cilia to operate normally• Approach trialed is to remove cells from body, add working copies of the gene and put the cells back• The working copies of the gene integrate themselves into random positions in the genome of the treated cells (repetition and cancer) ALBIO9700/2006JK
  7. 7. • A vector must be used to deliver the DNA containing the functional CFTR gene into the lung cells – Viral delivery systems • Adenoviruses (group of viruses that infect the membranes of the respiratory tract, eyes, intestines, and urinary tract) can be used/viruses which infect lungs • Virulence removed and genetically engineered to carry functional human CFTR gene • Either injection with genetically engineered viruses or inhale from an aerosol directly into the lungs – Non-viral delivery systems • Creation of a lipid sphere or liposome containing DNA • DNA can be compressed into a very small volume which may directly enter cells ALBIO9700/2006JK
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  10. 10. • There is not yet a successful example of treatment of CF by gene therapy because: – Current viral vectors have been found to stimulate allergic or other immune responses – Current liposome vectors have proved inefficient at delivering genes into cells – The effect of the therapy on chloride ion transport has lasted only a few days• A cure would require every one of the 50 x 10 13 cells in the body to be altered, which is not currently thought to be technically possible and would raise significant further ethical issues• To enable people with CF to have children would require germ-line gene therapy – changes are made to human gamete cells that are inherited by the next generation ALBIO9700/2006JK
  11. 11. • http://www.machinegraphics.com/animation/an• http://presenter.multicastmedia.com/links/CFF• http://learn.genetics.utah.edu/units/genetherap ALBIO9700/2006JK

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