8 Biotechnology- Biology for Human Welfare
8.4 Gene therapy
Gene Therapy
Dr V Malathi
Gene therapy is a cutting-edge biomedical procedure that includes changing or modifying genes. Gene therapy is used to restore normal function in cells, it is used to repress malfunctioning genes,it introduce therapeutic genes, or fix damaged genes. Gene therapy has enormous promise for treating cancer, genetic abnormalities, and other illnesses brought on by defective or missing genes.Both inherited genetic diseases (e.g., hemophilia and sickle cell disease) and acquired disorders (e.g., leukemia) have been treated with gene therapy.
How Does Gene Therapy Work?
The process of gene therapy involves adding, deleting, or changing genetic material in a patient’s cells.
The three main strategies of gene therapy include:
- Replacing a Mutated Gene : A functional copy of a gene is substituted for a defective or absent one.
Example: Replacing the faulty ADA gene to treat severe combined immunodeficiency (SCID). - Inactivating a Faulty Gene : A disease-causing gene that isn’t working properly is switched off.
For instance, turning off genes that encourage the growth of cancer. - Introducing a New Gene : To aid the body in fighting sickness, a whole new gene is added.
For instance, introducing genes to create therapeutic proteins to treat conditions like hemophilia.
Types of Gene Therapy
a. Germline Gene Therapy : Involves altering the DNA of germ cells, such as sperm, eggs, or embryos. Future generations will be affected by these inherited alterations.
Applications include the potential to treat hereditary illnesses like Huntington’s disease and cystic fibrosis while they are still in the embryonic stage. This type of gene therapy is not approved for use in humans in the majority of nations due to ethical considerations.
frequently used to treat genetic problems in diseases like cancer, and hemophilia.
a.In Vivo Gene Therapy: In this method the therapeutic gene is introduced into the patient’s body directly in to the target organs or tissues. It makes use of either non-viral or viral vectors. Example :Direct gene injection into muscle tissue to treat genetic diseases like muscular dystrophy. Challenges include accuracy in targeting, avoiding off -targets.
b. Ex Vivo Gene Therapy: Here cells from the patient are taken out, genetically altered in a lab, and then reintroduced into the body. This type of therapy is used in CAR-T Cell Treatment which involves altering immune cells to specifically target cancer. This type of therapy is advantageous as the controlled environment reduces risks of unintended effects.
Based on Therapeutic Approach
a. Gene Augmentation Therapy : This is the addition of a functional gene to replace a missing or damaged gene.
This is used for treating illnesses like muscular dystrophy and cystic fibrosis brought on by mutations that induce loss of function.
b. Gene silencing therapy : is defined as suppressing the expression of genes that are danger