Gene therapy is that the introduction of a traditional gene into an individual’s genome so as to repair a mutation that causes a genetic disorder. When a traditional gene is inserted into a mutant nucleus, it presumably will integrate into a chromosomal site different from the defective allele; although this might repair the mutation, a replacement mutation may result if the traditional gene integrates into another functional gene. Human gene therapy has been attempted only on somatic (body) cells for diseases like cancer and severe combined immunodeficiency syndrome (SCIDS).

1. ANUGYA JAISWAL
GAURAV SINGH
SHREYA SHAH
SHALINI

2. Content
 Introduction
 How does gene therapy work?
 Types of Gene Therapy
 Approaches in Gene Therapy
 Applications of gene therapy
 Gene Therapy in Cancer Treatment
 Treatment of various Inherited Diseases
 Case Study
 References

3. Introduction
Gene Therapy
introduction of traditional gene into individuals genome to prevent and cure various
diseases.
Concept introduced in 1960s.
Accomplished by-
1. Replacing mutated gene with corrected copy of gene.
2. Inactivating or Knocking out mutated gene.
3. Introducing new gene into the body to help fight a disease.
Diseases on which gene therapy based research is going on are Hemophilia, Tyrosinemia,
Hyperbilirubinemia, Cystic Fibrosis and many other cancers.

4. How does gene
therapy work?
 A carrier/vector is
genetically engineered to
deliver the gene.
 Viruses are modified so
they can't cause disease and
genetically engineered to
deliver the gene.
 The new gene delivered by
the vector will make a
functioning protein.

5. Types of Gene Therapy
SOMATIC CELL GENE THERAPY GERM LINE GENE THERAPY
• Therapeutic genes transferred into the somatic
cells.
• Therapeutic genes transferred into the germ cells.
Eg. Introduction of genes into bone marrow cells,
Blood cells, skin cells etc.
Eg. Genes introduced into eggs and sperms.
• Will not be inherited later generations. • It is heritable and passed on
to later generations.
• At present all researches directed to correct
genetic defects in somatic cells.
• For safety, ethical and technical reasons, it is not
being attempted at present.

6. Approaches in Gene
Therapy
 In vivo gene therapy:- direct
delivery of genes into the cells
of a particular tissue in the
body.
 Ex vivo gene therapy:-
transfer of genes to cultured
cells and reinsertion.

7. Applications of RDT in Gene Therapy
Treatment of cancer
In cancer, oncogenes gets activated causing tumour formation or the genes which
suppresses tumour formation gets inactivated.
The inactivated tumour suppresser gene’s effect can be reverted by introduction of
correct tumour suppresser gene.
Inactivation of oncogene is done by introducing a gene which codes for the
antisense mRNA for the mRNA produced by the oncogene.
Suicide gene therapy can also be used to kill the cancer cells by the introduction of a
gene that selectively kills cancer cells.
Introduction of a strong antigen producing gene into the tumour cells which is
recognized by the patient’s immune system then kill the tumour cells.

8. Treatment of inherited diseases
i. ADA-SCID (Adenosine deaminase- Severe Combined Immuno Deficiency)
Patients with ADA deficiency are unable to repel most sorts of infections.
Its caused by mutations within the ADA gene.
is inherited in an autosomal recessive manner.
GT involves replacing a replica of the non-working ADA gene with a working copy.
A retrovirus is engineered to contain the normal human ADA gene.
Reimplantation of the transgenic cells into the patient's bone marrow establishes a line of cells
with functional ADA gene.

9. ii. Cystic Fibrosis
an autosomal recessive disease.
occurs due to mutation in Cystic Fibrosis Transmembrane Conductance Regulator
(CFTR) gene which codes for cAMP protein.
cAMP protein is to regulate chloride channel, sodium channel and bicarbonate transport
in epithelial cells.
Mutated CFTR gene affects the cAMP protein level and its production.
Its treated through GT when correct CFTR gene is inserted into the targeted cells using
a suitable vector.

10. iii. Hemophilia
It is an inherited blood clotting disorder.
Body becomes unable to synthesize enough clotting factors.
It is of several types:
a) Hemophilia A/Classical Hemophilia: Body will be unable to synthesize clotting factor VIII.
b) Hemophilia B/ Chistmas disease: There will be reduced level of clotting factor IX.
A modified non-contagious virus is used as a vector to introduce the correct.
Gene coding for the clotting factor reduced in the blood by using gene therapy.
AMT-061 gene therapy is used to treat hemophilia B.
CRISPR technology is used to inactivate the gene causing clotting factor deficiency.

11. iv. Muscular dystrophy
occurs due to mutation in dystrophin gene located on the X chromosome.
causes interference in the production of muscle protein.
results in the deterioration in the muscle cells and the muscle cells are replaced by
connective or fatty tissues.
Crispr-Cas9 gene scissors is used to assemble the corrected dystrophin gene.
Duchenne dystrophy (DMD) gene used as correct dystrophin gene produces
utrophin.
Utrophin is similar to dystrophin structurally and have same protein binding sites.

12. Case study
Case study : Suggest that Gene therapy could one day cure HIV
HIV (Human immunodeficiency Virus) cause AIDS interferes with the body's ability to fight
infections.
If a patient’s immune cells could be modified to have two copies of particular mutation, they
could be used to cure HIV infection while reducing the risk of rejection. This kind of treatment is
known as Gene therapy, which has been approved by the US food and Drug Administration
(FDA).
A man who had been living with HIV since 2003 was also diagnosed with late stage Hodgkin's
lymphoma in 2012.
The doctors believed that his best treatment would be a transplant of healthy stem cells that give
rise new cells or healthy cells.
At the time there was no perfect Donor match for a patient. The donor's genes are slightly
different from the patient, with two copies of a mutation on a gene called CCR5.

13. Cont..
CCR5 is a protein on surface of the CD4 cells that acts a doorway for HIV virus to enter into
cell. Take away this entry way and CD4 cells will not be infected and the person will not get
HIV.
These mutations make it impossible for the most common form of HIV to infect immune cells
in the body. The patient had a slightly adverse reaction to his transplanted stem cells at first,
but after a year and a four month, there is no evidence of HIV in his blood. No medication will
continue.
Eighteen months later, he appears to be HIV free.
Another case, this kind of remission has been recorded in 2008. Name of patient Timothy
Brown also he was known by Berlin patient. He was also diagnosed with HIV. And he also
received stem cell transplants with CCR5 mutation as part of treatment for a different blood
cancer.
His cancer returned and he also required second transplant, and now he has been HIV free.

14. References:
Brown.Tr . (2010) . Production of Recombinant pharmaceutical . Volume 14 . PP – 286,287,288
Websites referred:
 https://www.slideshare.net/DeepakKumar2053/assignment-on-recombinant-dna-technology-and-
gene-therapy
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5178364/
https://www.biologydiscussion.com/dna/recombinant-dna-technology/top-5-applications-of-
recombinant-dna-technology-in-medicine/11935
http://www.genetherapynet.com/JoomlaTest2/index.php?option=com_content&view=article&id=164:d
iseases-treated-with-gene-therapy-&catid=97:patient-information&Itemid=14

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