Gene therapy involves inserting genes into cells to treat disease. It was first tested in animals and then used in humans. The first approved gene therapy experiment occurred in 1990 and treated a child named Ashanti DeSilva for ADA-SCID. There are two main types of gene therapy - somatic cell gene therapy, which targets non-reproductive cells and is preferred since genetic changes are not passed to offspring, and germ line gene therapy, which targets reproductive cells. A common method is ex vivo gene therapy, which involves removing cells like bone marrow, modifying them in a lab, and returning them to the patient.

2.  It is the process of inserting genes into cells to
treat a disease.
 It involves genetic manipulation in humans or
animals to correct a disease, & keep the organism
in a good health.
 The initial experiments are carried out in animals
and then in humans.
 The first approved gene therapy exp. Occurred on
September 14,1990 in US, when ASHANTI
DESILVA was treated for ADA-SCID.

5.  SOMATIC CELL GENE THERAPY:- the non
reproductive(sex cells) are called somatic
cells.
 GERM CELL GENE THERAPY:- the
reproductive (sex cells)of an organism is
called germ cell line.
 THE GENETIC ALTERATIONS IN SOMATIC CELLS
ARE NOT CARRIED TO THE NEXT GENERATION
THEREFORE SOMATIC CELL GENE THERAPY IS
PREFERRED.

6.  EX VIVO GENE THERAPY:-
involves the transfer of genes
in cultured cells(bone marrow)
which are then reintroduced
into the patients.
 It can be applied to only
selected cells e.g. bone
marrow whose cells are
cultured in the lab.

7.  EXAMPLE:- to correct ADA. Performed on a
4yr old girl ASHANTHI Desilva.
 Was suffering from SCID.
 Caused due to defect in gene coding for
ADA.
 Deoxy adenosine accumulate &destroys T
lymphocytes.
 Disrupts the immunity suffer from infectious
disease &die at young age.

8. IN VIVO GENE THERAPY:- direct delivery of genes
into the cells of a particular tissue.
Transduction takes place within the patient’s own
cells.
Example:- in patients with CFTR is absent due to
gene defect.
In the absence of CFTR chloride ions conc. within
the cells &it draws water from surrounding.
Leading to the accumulation of sticky mucous in
respiratory tract &lungs.
Treated by in vivo replacement of defective gene by
ADENOVIRUS VECTOR.

9.  As gene therapy involves a greater risk. There
are several regulatory agencies whose
permission must be sought before undertaking
any work related to gene therapy.
RECOMBINANT DNA ADVISORY
COMMITEE(RAC) it is a supervisory body of
the National Institute of the Health,USA, that
clears proposal on exp. involving gene therapy.