Gene therapy is a procedure that introduces functional genes into cells to treat diseases.
Gene therapy uses recombinant DNA techniques to replace or manipulate troubled genes. The introduction of a healthy gene will correct information that is wrong or missing from an individual’s DNA, which can lead to the cure of the disease or alleviation of its symptoms.
In summary, we can say that gene therapy is the exchange of defective genes for healthy genes.
The advance of Genetics contributed to the emergence of gene therapy, enabling scientists to modify an individual’s set of genes.
Currently, gene therapy is in full development. Every day new studies and discoveries appear, representing an opportunity of cure or treatment for several diseases, such as cancer, diabetes, hemophilia and AIDS.
In Brazil, treatment with gene therapy is not yet a reality. However, there are several Brazilian scientists involved in research on gene therapy.
How does gene therapy work?
The technique of gene therapy consists of introducing a healthy gene into the body, considered the gene of interest (therapeutic gene). This gene is found in a DNA or RNA molecule that must be introduced into an organism.
However, DNA is hardly introduced directly into an organism. A charger is needed to transport the DNA to its destination, where the gene exchange will take place. This loader is called a vector. The vectors can be plasmids or viruses.
Generally, the virus is chosen to be the vector for a particular gene. That’s because viruses are, of course, specialized in invading cells and introducing genetic material into them. However, to be a vector, the virus undergoes modifications, in which genetic information is removed that can trigger an immune response, only its essential genes are kept.
The introduction of the gene into the body can occur in two ways:
- In vivo form : the vector is introduced directly into the organism. This form is considered more efficient and less expensive. However, the correct addressing is necessary, if a gene is destined for the liver, it must be ensured that it reaches this organ and not the pancreas, for example.
- Ex vivo form : the individual’s cells are removed, modified and reintroduced. It is a more difficult method, but easier to control.
Types of Gene Therapy
There are two types of techniques in gene therapy: germline and somatic.
The germinative technique consists of introducing the genes into the zygote, the cell resulting from fertilization, or in the eggs and sperm. Thus, the cells that originate from these germ cells will now have the gene of interest in their genome.
The somatic technique consists of introducing genes into somatic cells, that is, non-germ cells. Somatic cells make up most of the body. This technique is more used and there is no transmission of genes to the descendants, as in the germinative technique.
Gene Therapy and Diseases
Initially, gene therapy was focused only on the treatment of monogenic diseases, characterized by the absence or deficiency of a gene. Examples of monogenic diseases are cystic fibrosis, hemophilia and muscular dystrophies.
However, currently, gene therapy has also focused on the treatment of acquired diseases, as these have a higher incidence in the human population. Thus, AIDS and cancer became the object of study of gene therapy.
Learn more about genetic diseases .
Today, gene therapy has already shown advances in the treatment of some diseases. For example, in 2013, American scientists were able to genetically modify T lymphocytes and make them resistant to the entry of the HIV virus . Studies with humans are still lacking, but the results found represent a possibility of a cure for the disease.
As gene therapy is still improving and growing, there are also risks. In 1999, a patient died after the injection of a vital vector during a clinical trial. In addition, there are still several ethical issues involved with the technique.