This document provides an overview of gene therapy. It discusses the definition of gene therapy as inserting genes into cells to treat disease. The history of gene therapy is described, including early research in the 1970s and the first human clinical trial in 1990 to treat ADA deficiency. The document outlines the main types of gene therapy as somatic, germline, and preventative. It also discusses gene delivery methods using viral and non-viral vectors and the advantages and disadvantages of gene therapy.

1. Gene Therapy
Presented by-
Yamini Meshram
M.Sc Sem-3 (Biotechnology)
Dr. Ambedkar College, Deekshabhoomi, Nagpur
Department of Biochemistry and Biotechnology

2. Content
• Introduction
• History
• Types
• Gene Delivery
• Vectors
• Advantages and Disadvantages
• Reference

3. Introduction
• Gene therapy:- Gene therapy is the insertion of genes into an
individual's cells and tissues to treat a disease, and hereditary
diseases in which a defective mutant gene is replaced with a
functional one.
• In most gene therapy studies, a "normal" gene is inserted into the
genome to replace an "abnormal," disease-causing gene.
• A carrier called a vector must be used to deliver the therapeutic
gene to the patient's target cells.

4. History
• In 1972, Theodore Friedmann and Richard Roblin published a paper in
Science called "Gene therapy for human genetic disease?" which cited
Stanfield Roger's proposal in 1970 that "good DNA" could be used to
replace defective DNA in people with genetic disorders.
• The first patient to be treated with gene therapy was a four year old girl
treated at the NIH Clinical Center in 1990. She had a congenital
disease called adenosine deaminase (ADA) deficiency which severely
affects immunity and the ability to fight infections.
• In 1985, Anderson and colleague Michael Blease started working
together to demonstrate how cells from people with ADA deficiency
could be modified in tissue culture. They used a retrovirus as a vector
to carry the correct ADA gene into the cells.

5. • In 1986, they tried transferring the correct genes into the bone marrow
of animals, but in 1988, found that transferring them to white blood
cells was much more successful, with a dramatic increase in the
amount of the correct genes being taken up by cells.
• In 1989, the researchers teamed up with Dr. Steven Rosenberg to test
how safe and effective the gene therapy would be in cancer patients.
The team cultured tumor infiltration lymphocytes cells (TIL cells)
from people with malignant melanoma.
• In 1990, the four-year old girl and another nine-year old girl with ADA
deficiency were infused with their own corrected cells over two years
and in 1993, the team used the gene therapy to treat newborn infants
with ADA deficiency. The corrected ADA genes were transferred to
immature blood cells obtained from the babies' umbilical cords.

6. Types
• Somatic Gene Therapy:- In somatic gene therapy, the therapeutic
genes are transferred into the somatic cells, or body, of a patient
• Germ Line Gene Therapy:- In germ line gene therapy, Germ cells,
i.e., sperm or ovum, are modified by the introduction of functional
genes, which are integrated into their genomes. This would allow the
therapy to be heritable and passed on to later generations.
• Preventive Gene Therapy:- Preventive gene therapy is the repair of a
gene with a mutation associated with a progressive disease, prior to the
expression of a medical condition, in order to prevent that expression.

7. • Gene delivery is the process of introducing foreign DNA into
host cells.
• By two methods genes can be delivered. They are as follows:-
 Viral Vectors.
 Non Viral Vectors.
Gene Delivery

8. Vectors
Viral Vectors
• All viruses bind to their hosts and introduce their genetic material into
the host cell as part of their replication cycle.
• A number of viruses have been used for human gene therapy.
• Example:- retrovirus, adenovirus, lent virus, herpes simplex virus,
vaccinia, pox virus, and adenoassociated virus.

9. Non-Viral Vectors:
• Non-viral methods can present certain advantages over viral
methods, such as large scale production and low host
immunogenicity.
• There are several methods for non-viral gene therapy, for example
the injection of naked DNA, electroporation, the gene gun,
magnetofection, and the use of oligonucleotides, lipoplexes,
dendrimers, and inorganic nanoparticles.

10. Advantages
• Gene silencing is a concept that in itself is self-efficient for
management of many diseases.
• Gene therapy has the potential to eliminate and prevent hereditary
diseases, such as cystic fibrosis, and is a possible cure for heart disease,
AIDS and cancer.
• Gives an advantage to a person born with genetic disorder to live life in
a normal way by replacing non-functional gene with a functional one.

11. Disadvantages
• Irregular immune responses.
• Viral vectors may introduce toxicity, as well as immune and
inflammatory responses.
• Multi-gene disorders such as heart disease, high blood pressure,
Alzheimer’s disease, arthritis, and diabetes cannot be treated through
this therapy as conditions or disorders that arise only from mutations
in a single gene are the best candidates for gene therapy.
• Chances of inducing iatrogenic (physician induced) tumours in
human beings.
• Short-lived nature of gene therapy.

12. Reference
• https://www.sciencedaily.com/terms/gene_therapy.htm
• https://www.news-medical.net/health/Gene-Therapy-History.aspx
• http://www.biotechnologynotes.com/gene-therapy/gene-therapy-
meaning-types-advantages-and-disadvantages/823