Gene therapy is the insertion of genes into a patient's cells to treat disease. It works by replacing a defective gene with a functional one. The basic process involves identifying the faulty gene causing a condition, delivering a working version of the gene to the affected cells using a viral vector, and having the gene expressed within the target cells. Recent advances include the first FDA-approved gene therapy for an inherited disease in 2017 and CAR-T therapies using genetically engineered immune cells to treat some cancers. While still early in development, gene therapy has shown success in clinical trials for diseases like cystic fibrosis and is a promising field of research.

1. GENE THERAPY
PREPARED BY : SOURAV KUMAR BISWAL
DEPARTMENT OF PHARMACY
TRIPURA UNIVERSITY(A CENTRAL UNIVERSIRTY)
SURYAMANINAGAR,799022

2. INTRODUCTION
• 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 allele is replaced
with a functional one.
• Although the technology is still in it’s infancy, it has been used with some success.
• 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.
• Currently, the most common type of vectors are viruses that have been genetically
altered to carry normal human DNA.
• Target cells such as the patient’s liver or lung cells are infected with the vector.
• The vector then unloads it’s genetic material containing the therapeutic human
gene into the target cell.

3. THE GENE THERAPY PROCESS
The basic steps of gene therapy include:
1.The faulty gene that causes a specific
condition must be identified.
2.The location of the affected cells in the
body’s tissues or organs must be
pinpointed.
3.A working version of gene must be
available.
4.The working version of the gene has to be
delivered to the cell.

4. Figure 1: In vivo gene transfer. The in vivo strategy is based on the production of replication deficient
virus in vitro followed by direct injection (or infusion) of the virus into an organ system. The virus
genetic material will incorporate into cells and therapeutic genes will be expressed.

5. Figure 2: Ex vivo gene transfer. The ex vivo strategy is based on the utilisation of a
surrogate cell that is infected with virus in vitro. The surrogate cell is subsequently
transferred to the target tissue and expresses the therapeutic gene.

6. CLINICAL APPLICATION OF GENE THERAPY
• Although the field of gene therapy has experienced significant setbacks and
limited success, it is one of the most promising and active research fields in
medicine.
• Over the next decade, the relevance of gene therapy to medical practices will
increase and it will become important for physicians to understand the basic
principles and strategies that underlie the therapeutic intervention.
• Basically, two strategies are used for gene delivery, one is “in vivo gene therapy’
and another is “ex vivo gene therapy”.
• It is very useful to cure diseases caused by single gene mutation.
• For examples- Cystic fibrosis(caused by mutations in a gene on chromosome 7) and
Duchenne muscular dystrophy(caused by large deletions or insertions of the
dystrophin gene)….etc
• It is also helpful to treat diseases like Alzheimer, cancer and atherosclerosis.

7. RECENT ADVANCES IN GENE THERAPY
• Gendicine, the first approved anticancer drugs based on the use of gene therapy
principle, is based on the use of oncolytic viruses.
• 2017 was the year of gene therapy breakthroughs.
• In march, researchers announced that a teenage boy in France had been cure of
sickle cell diseases after receiving an experimental gene therapy developed by
Bluebird Bio.
• This year the FDA approved two pioneering treatments, Kymriah and Yescarta, that
use a patient’s own immune cells to fight rare types of cancer. Called CAR-T
therapies, these “living drugs” are made by extracting T cells from patients and
genetically engineering them to go after and destroy cancer cells.
• In December, the FDA approved the first gene therapy for an inherited disease.
The treatment, called Luxturna, aims to correct a mutation responsible for a range
of retinal diseases that make people gradually go blind.
• In human tests, the treatment has restored vision for more than two dozen
patients who were losing their sight.

8. PRINCIPLES OF DNA AND RNA ESTIMATION
• The estimation of nucleic acids (DNA and RNA) is performed to determine the
average concentrations of DNA or RNA present in a mixture and also their purity.
• There are two main approaches used by scientists to estimate the concentration of
nucleic acids in a solution.
• These are spectrophotometric quantification and UV fluorescence tagging in
presence of a DNA dye.
• Spectrophotometric analysis is based on the principles that nucleic acids absorb
ultraviolet light in a specific pattern.
• Another method to assess DNA and RNA concentration is to tag the sample with a
fluorescent tag, which is a fluorescent dye used to measure the intensity of dyes
that bind to nucleic acids and selectively fluoresce when bound.
• The later is useful where concentration is too low to accurately assess with
spectrophotometry and in cases where contaminants absorbing at 260 nm make
accurate estimation by the method impossible.

9. REFERENCES
• https://www.sciencedaily.com
• https://www.betterhealth.vic.gov.au
• https://pmj.bmj.com
• https://www.ncbi.nlm.nih.gov
• https://technologyreview.com
• https://www.wikipedia.org

10. THANK YOU