Cystic fibrosis is a genetic disease caused by a mutation on the CFTR gene that prevents proper salt movement in and out of cells. This causes thick mucus to build up and block ducts in the lungs and other organs. Gene therapy offers a potential cure by delivering a healthy copy of the CFTR gene to replace the defective one using virus vectors. However, current limitations include the vectors randomly inserting into DNA which can cause harm, and the long-term effects are still unknown. While still experimental, gene therapy could provide a cure rather than just treatment of symptoms if these challenges can be overcome.

1. C Y S T I C
F I B RO S I S
G E N E T I C
T R E AT M E N T
Advantages of genetic therapy
(A pro of gene therapy is that it doesn't
cover up what's wrong but fixes the
'problem'.) (Ndsu.edu ) CF is a painful
disease on the patient as well as their
families; it has a boundless social impact.
The genetic treatment takes a long time to
work and is currently does not permanently
solve the problem, but is helps cure it,
instead of treat it. All current treatments are
meant to help ease the pain and make the
disorder easier to live with. But genetic
therapy is capable of creating a normal
painless life for CF suffers. Also gene
therapy is a rapidly growing research
industry reinforced by modern technology.
When gene therapy is completely developed
it will prevent CF from killing its victims
and might stop it from being inherited in
future generations.
Maryam Hamouda
Science Grade 10 C
Genetics and Biotechnology
Limitation of genetic therapy
An obvious limitation of genetic therapy is
that it still not developed. So far, the
normal gene vector is inserted randomly
into the DNA causing many complications
in the phenotype of the body. This may
harm or even kill the patient. Also germ
line therapy is that it not only affects the
sufferers, but also the generations after
them. The researchers still haven’t
established the long-term affect of this
alteration in DNA in germ line therapy. It
could create new disorders in future
generations. Finally, technology current
isn’t adequate enough for gene therapy to
treat many diseases. There are so many
conditions for gene therapy to be used on a
patient. (All gene therapy at this stage is
experimental and cannot be used for any
disease.) (The UK Cystic Fibrosis Gene
Therapy Consortium)
The Problem
A mutation on the CFTR gene on
chromosome 7 most commonly caused by a
three-paired deletion stops salt from moving
in a out of cells causing symptoms like poor
digestions and severe coughing. If not
treated, most CF patients will developed
lung infections and are threatened by death
before the age of 20. The thick mucus also
blocks ducts in the pancreas and liver so
digestive enzymes can't get into the
intestines. (Without these enzymes, the
intestines cannot properly digest food.)
(PubMed Health)
People who have this
disorder often do not get
the required nutrition and
do not grow normally.
Therefore, there is a
treatment that solves this
problem at its source;
this solution is called
Gene Therapy.

2. What is cystic fibrosis?
What causes Cystic Fibrosis?
CF sufferers inherit a deficiency in a gene on chromosome 7 called
CFTR (cystic fibrosis trans membrane conductance regulator). The
proper gene is in charge of producing proteins that assist salt
(sodium chloride) enter and exit cells easily. When the gene doesn’t
work properly, the movement of salt is blocked and this creates
thick tissues of mucus on the outside of the cells. The lung cells are
the most severely affected cells by this blockage. (This mucus clogs
the airways in the lungs, and increases the risk of infection by
bacteria.)
(Genetics Home Reference)
CF is a recessive disorder meaning that both parents must pass on
the muted gene to their child.
The infant must be
homozygous for the defective
CFTR gene on chromosome 7
to get the disease. If only one
parent passes the gene to
their child, then the child will
not suffer CF, but will be a
carrier of the defected gene.
Carriers do not show any
symptoms of the disease but
can pass it down to their children.
Chances of inheriting this
disease vary depending on the
parents’ genotypes. A child
suffering CF can have two
healthy parents, but they were
both carriers and they passed
this copy of the gene to him.
Genetic Treatment
The first type is called ‘Germ line gene
therapy’. Germ line therapy would change the
persons DNA by altering the original genes in
all the body cells. This not only affects the
patient’s health but also future generations
wouldn’t inherit it through this person.
The other form of treatment is called ‘somatic
gene therapy’. This form of treatment affects
the body but does not change it. Somatic gene
therapy involves changing the defective gene in
the individual but the change won't be inherited
by the next generation. Somatic gene therapy is
the most popular and recommended since it
doesn't have the ethical considerations like
germ line therapy.
The treatment will only work if the defective
gene is replaced in all cells. To replace a
dysfunctional gene with a normal one, delivery
vehicles called vectors containing the correct
gene are used. This vector is cut in a weakened
adenovirus and filled with the normal gene.
These viruses are originally responsible for
multiple respiratory illnesses, but when they are
weakened they are harmless. These viruses are
then inserted into the cell to find its way to
chromosome 7 where it should replace the
mutated gene. But first, the healthy gene will
insert itself randomly in the DNA. This might
be harmful or helpful to the patient depending
where the gene is inserted, and this in random
insertion might change a certain phenotype in
the patient’s body. Further research must be
carried to find a way in which the gene can be
inserted in the DNA without being harmful.
(Cystic fibrosis is an inherited disease characterized by the buildup of thick, sticky mucus that can damage many
of the body's organs.)
(Nhs.uk) The symptoms of this disorder include gradual damage in the respiratory system
and persistent problems in the digestive system. The severity of the disease varies among various sufferers. Cystic
fibroses was considered a lethal disease of childhood because suffers are born with it. Currently, developed
biotechnology treatments help manage the disease affectively and expand the lifespan of cystic fibrosis patients
till adulthood.
Genetic Treatment
Gene therapy is a treatment currently in clinical
trials, in which the healthy CFTR gene is
inserted into the lung cells of a patient to correct
the defective gene. It offers the most effective
solution because it tackles the root cause of CF
rather than just treating the symptoms. Since all
the cells in the body carry the same faulty gene,
the sticky mucus builds on all organs. By adding
copies of the normal gene into the body the
correct protein will be produced as well as the
defective one. The mutated gene will not stop
the normal one form working, so inserting the
gene in the affected areas would fix the problem
in the affected tissue. Treating the lungs
genetically is feasible through an inhaler, which
delivers the proper CFTR gene into the lung
tissues.
Gene therapy identifies the defective gene and to
corrects it by replacing it with the normal gene.
There are two types of gene therapy that are still
being developed by researchers and haven’t
been used on humans.