Role of gene therapy in modern medicine

1. Universities Press
Universities Press
Rafi M D: Textbook of Biochemistry for Medical Students (2nd Edn)
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2. Universities Press
Universities Press
Rafi M D: Textbook of Biochemistry for Medical Students (2nd Edn)
Gene Therapy

3. Universities Press
Universities Press
Rafi M D: Textbook of Biochemistry for Medical Students (2nd Edn)
Gene therapy involves correcting defective
genes. Gene therapy involves isolating normal
genes and inserting them into diseased cells, so
that the normal genes are expressed, allowing
the diseased cells to return to a normal state.
Gene delivery protocols
• Ex-vivo gene transfer
• In-vivo gene transfer

4. Universities Press
Universities Press
Rafi M D: Textbook of Biochemistry for Medical Students (2nd Edn)
GENE TRANSFER TECHNIQUES
Viral vectors
• Retroviruses
• Adenoviruses
• Herpes viruses
Transfer hrough liposomes
Receptor-mediated endocytosis
Artificial chromosome vectors
Antisense therapy
Target tissues for gene transfer

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Universities Press
Rafi M D: Textbook of Biochemistry for Medical Students (2nd Edn)
Some diseases treated by gene therapy

6. Universities Press
Universities Press
Rafi M D: Textbook of Biochemistry for Medical Students (2nd Edn)
Use of retrovirus for gene therapy [The retrovirus carries an RNA copy of the therapeutic gene into the cell.
The endosomecontaining virus dissolves and the viral RNA and reverse transcriptase are released into the cell. The enzyme copies the
RNA into a doublestranded DNA that eventually integrates into the host DNA. Transcription and translation of this DNA (the therapeutic
gene) produces the therapeutic protein. Note that the virus does not multiply since its genes were removed and replaced by the RNA
copy of the therapeutic gene]

7. Universities Press
Universities Press
Rafi M D: Textbook of Biochemistry for Medical Students (2nd Edn)
DISEASES TREATED WITH GENE THERAPY
 A defect in the adenosine deaminase (ADA)
gene located on chromosome 20 causes
severe combined immunodeficiency
syndrome (SCID)
 Familial hypercholesterolemia
 Cystic fibrosis

8. Universities Press
Universities Press
Rafi M D: Textbook of Biochemistry for Medical Students (2nd Edn)
• Gene therapy in cancer
• Antisense therapy

9. Universities Press
Universities Press
Rafi M D: Textbook of Biochemistry for Medical Students (2nd Edn)
The process of RNA interference

10. Universities Press
Universities Press
Rafi M D: Textbook of Biochemistry for Medical Students (2nd Edn)
RNA interference, a natural mechanism
evolved against the invasion of RNA viruses,
is also used to block the expression of
oncogenes.

11. Universities Press
Universities Press
Rafi M D: Textbook of Biochemistry for Medical Students (2nd Edn)
The advent of gene therapy in the past few
decades offers the promise of many
revolutionary changes in clinical medicine.
FUTURE SCOPE OF GENE THERAPY
• Curing genetic disorders permanently
• Correcting cancer genes and inducing
cancerous cells to make toxins so that they
kill themselves
• Blocking viral genes (e.g. HIV)
• Creating stem cells from somatic cells.