As per several genome research organizations, a sizeable percentage of diseases acquired by newborns are genetic, which means the diseases were acquired through hereditary or mutations.
In simpler terms, when the egg and the sperm (genetic material) fuse, the embryo formed will acquire some hereditary traits that may carry diseases. A random mutation, although rare, may cause an extremely rare genetic condition.
Rather than making futile attempts at discovering newer drugs for genetic disorders, in May 1989, scientists made the first successful attempt at modifying human DNA by injecting favourable genes into the nucleus of the cell. This method, called gene therapy, ever since has been advancing by leaps and bounds.
Coupled with the latest genetic editing tool called CRISPR/CaS9, gene therapy has lead to a new idea – a society free of diseases.
The introduction of foreign DNA into a patient’s cell’s nucleus to replace a mutated gene or a missing gene that may be causing a certain disease, is called Gene Therapy.
The new DNA usually contains a functioning gene to correct the effects of a harmful mutation or missing gene.
Although they, too, introduce foreign DNA, organ transplants or bone marrow transplants aren’t categorized as genetic therapy methods. The goal of the method must be to show pure therapeutic effects in order to be regarded as a gene therapy procedure.
How Does It Work?
- Some sections of the DNA/genes contain instructions for making useful proteins. These sections are packed in a carrier such as a virus, a bacterium or a plasmid.
- The carrier transfers the new gene into the cells of the patient in question.
- The DNA/gene usually is accepted by the cell, leading to the production of the therapeutic protein required.
Types of Genetic Therapies
- Gene Augmentation Therapy: Treats diseases (such as cystic fibrosis) caused by a mutation that stops a gene from producing a functioning protein (usually). This procedure adds DNA carrying a functional copy of the lost gene and transfers it back into the cell.
- Gene Inhibition Therapy: Ideal for the treatment of infectious diseases, a few types of cancers, and inherited diseases caused by “misbehaving” genes. This method is achieved by inhibiting the expression of the defective gene.
- Killing of specific cells: Achieved by destroying the DNA of certain groups of cells, especially cancerous ones. This is either achieved by the DNA’s “suicide” gene that kills the diseased gene using its toxic chemicals or by “marking” the cells so that body’s natural immune system can identify and attack it.
- “Germline” Therapy: The latest addition in gene therapy which lead to the concept of genetic editing. The healthy gene is injected into the nuclei of the eggs or sperm or the embryo and treated therein. The effects will be passed onto the child and subsequent generations. This procedure has the potential to not only rid the patient’s generations off the disease, but also open newer avenues to modify the offspring’s entire genetic makeup (genome).
Challenges of Gene Therapy
- Delivering the gene to the right cell. A wrong target would be inefficient and could also worsen the patient’s condition further.
- Cells avoiding immune response after mistaking healthy genes for harmful intruders.
- The disruption of other genes can be a major problem, if the procedure goes wrong.
- Most genetic disorders are rare and their treatment comes under personalized medicine. This may be super-effective but also an expensive endeavour.
With techniques such as “germline” therapy opening up the doorway to new possibilities such as genetic editing, the Society needs to tighten its noose around research organizations’ ethics without hampering scientific progress and the prospects of a future rid of diseases.