Our body's genetic information is stored in 23 paired chromosomes in the nucleus of our cells. Sections of our DNA is known as Gene and we have two copies of each gene with one copy from each of our parents. They give instructions on how to create proteins that determine how our body functions and a change to these genes would cause a drastic change in body functions and activities.
A lot of people have genetic diseases, and they undergo several therapies of which one is Gene Therapy, which is the introduction of DNA into a patient with a genetic disease to treat the disease. This new gene causes the functioning of the gene. Genetic diseases occur as a result of a non-functioning or mutated gene, leading to other genes being affected. This therapy has to do with removing the faulty gene from the diseased patient and inserting a newly synthesized gene into the patient to treat the disease. If there is a patient with a faulty gene in a patient, Gene Therapy has to do isolating the faulty gene where the faulty gene is identified and removed followed by the attachment of a functioning gene to the DNA.
Gene Therapy didn't just appear from the sky, it was discovered in 1980 by Martin Cline, and between 1989 and since then, there have been thousands of clinical trials with Gene Therapy. Some Gene Therapy has been approved by the FDA including companies like Spark Therapeutics, and Novartis, also Gene therapy drugs Novartis Zolgensma, and Alnylam's Patisiran were approved as well. In 1990 gene therapy was used to treat Adenosine deaminase Severe Combine Immunodeficiency where retroviral-mediated transfer of the adenosine deaminase (ADA) gene was performed.
Gene therapy exists in two types namely; Somatic Cell Gene Therapy, and Germ Line Gene Therapy.
Somatic Cell Gene Therapy has to do with the transfer of therapeutic genes into somatic cells. The somatic cells are bone marrow cells, blood cells, and skin cells. With Somatic cell gene therapy, the generations may not inherit the genes. While Germ Line Gene Therapy has to do with the transfer of the therapeutic gene into the germ cells such as Eggs, and Sperm. This gene therapy can be inherited.
Gene therapy can be done in vivo or Ex vivo with In vivo gene therapy being the direct delivery of the therapeutic gene into the target cells in the patient's body. This delivery would be done using either viral or non-viral vectors. The viral vectors include retrovirus vector system, adeno virus vector system, Adeno-associated virus vector, herpes simplex virus vector, non virus vector systems would include Pure DNA construct, DNA molecular conjugate, Lipoplexes, Human artificial chromosome. To perform gene therapy, Gene guns and Microinjections can be used in physical methods, while chemicals such as detergents, and lipofection can be used.
In the case of diseases such as Cystic fibrosis, the patient suffers from a lack of Cystic Fibrosis Transmembrane Regulator causing the lungs and the respiratory tract to accumulate mucus. To treat this with Gene Therapy, using the Adenovirus Vector to insert the CFTR gene is required. The Adenovirus Vector is harmless and the gene is inserted into it. The virus and the gene are inhaled by the patient, or given in the form of medicine causing the gene to get to the membrane of the lungs getting to the lung cells where it will enter into the cell membrane of the lung cell, then to the nucleus of the lung cell. The CFTR will then be inserted into the lungs.
In the case of Ex vivo Gene therapy, that has to do with a case such as Adenosine deaminase Severe Combine Immunodeficiency, a bacteria that carry the plasmid with cloned normal human ADA gene is used as well as a genetically disabled retrovirus vector, where the ADA is inserted into the retrovirus vector. The virus doesn't contain virulent genetic material. From the patient, T-cells with disabled ADA genes would be isolated after which the virus is incorporated into the T-cells to cause the retrovirus with the ADA gene to infect the T-cells. They will be cultured t allow for growth and then they would be implanted into the patient to allow for the production of ADA.
A lot of people suffer from conditions that include Alzheimer's disease, Parkinson's disease, cancer, or other genetic disorders. In the future gene and cell therapy would surely change medicine.
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