Gene therapy is among the most scrutinized medical applications. Genetic therapy characterizes the introduction of genes with the ability to prevent a disease from progressing and preferably to cure the disease. A normally functioning gene is introduced into a cell where there are genetic anomalies or defects. In light of this, individuals, tissues or cells which have been subjected to genetic manipulation or modification are categorically transgenic. The purpose of genetic therapy is significantly the elimination of cancerous cells and pathogens, correct genes, which are defective, prevention of cardiovascular diseases and neurological disorders.
Types of Genetic Therapy
The application of genetic therapy is characterized into germ-line or somatic gene therapy (Lanza, Langer, & Vacanti, 2007). Somatic gene therapy involves genes which have no direct relationship to reproduction. Therefore, treatments based on somatic gene therapy do not have an impact on subsequent offspring produced by the patients. This is because genetic modifications on the parents are not transmitted to their offspring (Bertolotti, 2012). For instance, where genes are introduced in a tissue or an organ for the purpose of inducing enzyme production; such alterations have no subsequent impact on the patient’s genetic composition. Therefore, the introduced genes are not transmitted to children born after the therapy. Somatic gene therapy has an impact of repairing dysfunctional organs; hence the application of gene therapy has significant contributions to human health and development (Bertolotti, 2012).
A significant application of gene therapy is the creation of DNA vaccines. These enable the immune system of subjects to counteract and prevent the occurrence of defined diseases, an action which is similar to that observed from conventional vaccines. Meanwhile, Germ-line cell therapy is premised on the introduction genes into reproduction cells with the intention of making a substantive change on the genetic makeup of the resulting offspring. Germ-line genetic therapy aims at introducing unique genes, which improve upon the pre-existing genetic composition of the subject. Genetic changes made as a result of germ-line genetic therapy are often transmitted to subsequent cells.
Incidents of Genetic Defects
The occurrence of genetic related diseases is subject on the nature of individual genetic composition. Therefore, an individual’s genetic makeup may comprise both normal and defective genes. In most instances, defective genes are discovered when a disease or an abnormality presents itself. The occurrence of a disease associated with genetic defects may manifest on individuals who are closely related to the patient (Giacca, 2010). Therefore, family members may be carriers or subjects of genetic defects. Various genetic related diseases and disorders have been identified; however, these vary on the degree in which they impact a patient’s health. While genes have been attributed to an individual’s affinity for infections, other factors such as lifestyle, diet and environment are equal contributors to the occurrence of disease.
Mostly individuals who are carriers of defective genes remain unaffected since they have a single copy of the defective gene. Consequently, the genetic disease is expressed by a combination of two copies of the defective gene; therefore, a significant number of people do not manifest the respective genetic disease. In light of this, greater incidents of genetic diseases are observed in children from parents of the same lineage. However, in the event that the defective gene is dominant, the associated disease can manifest on anyone carrying the defective gene (Lanza et al., 2007). Meanwhile, the presence of a dominant defective gene in an individual does not imply the occurrence of disease. However, combinations of other factors such as the environment are significant to the manifestation of various diseases. For instance, coronary diseases often have a genetic aspect; however, the occurrence of the disease is significantly impacted by lifestyle and diet (Hajjar, 2013).
Gene therapy requires gene coding for diseases to be identified precisely. There have been notable developments in the identification of genes associated with incidents of various diseases such as heart diseases and Alzheimer’s disease (Giacca, 2010). The identification of these genes has enabled accurate diagnosis of diseases in patients. This is a significant development if the treatment of genetic disease since they be diagnosed accurately without subjecting the patient to a battery of unnecessary tests (Giacca, 2010). The advances in biotechnology have made it easy to identify and detect abnormal genes. These have ensured that genetic therapy is delivered to the target in an effective, accurate and controlled manner.
The use of appropriate techniques in the delivery of DNA is critical since there must be an accurate reception of the appropriate genes by the target cells. For instance, naked DNA can be deployed directly to the affected cells or unique vectors can be used to transfer genes to the target cells in a more efficient and faster way. These vectors include viruses or plasmids which are used to transfer recombinant DNA between cells. Retroviruses comprise unique Ribonucleic Acid viruses which can place their nucleic acids into the target cells (Escors, Breckport, Arce, Kochan, & Stephenson, 2012). Other vectors include retrotransposons, Adenovirus and liposomes which are used to place and integrate genes into the target cells. The use of retrovirus aims at removing any harmful genes while appropriate corrective genes are used to replace the removed harmful genes. Consequently, the resulting restructured retrovirus is subsequently introduced into the subject.
Vectors are faced with a challenge since the patient’s immune system may resist them. Therefore, their ability to survive and accomplish delivering the corrective genes to the targeted cells is critical. Since, the action of the virus is through the infection of the target cells, the immune system reacts to this by counteracting and neutralizing the retrovirus (Lanza et al., 2007). Additionally, the viruses that survive the immune system must breach the cellular membranes in order to combine its genome with that of the host cell where the therapeutic genes are introduced into the infected cells.
The integration of the virus genome and the infected cell’s genome is a random act; however, this should take place in a non essential area of the DNA to the target genome (Escors et al., 2012). This prevents the occurrence of complications. Consequently, the gene being introduced should be transcribed and expressed to ensure that the correct enzyme is produced. Significantly, the use of direct injections of the therapeutic genes into the affected areas have been found to have more success in preventing the reactions associated with the immune system fighting the delivery vectors (Bertolotti, 2012). For instance, the direct injection of genes in treating lung cancer suppresses the growth of the cancerous tissue.
Risks of Gene Therapy
A significant consideration of gene therapy is the potential for ephemeral advantage to the patient. This has been observed in various clinical trials where the effects of the gene therapy would last for a number of weeks or months followed by the subsequent emergence of the disease (Giacca, 2010). This has been attributed to a decrease in the modified cells especially in cases of somatic gene therapy. These cells are differentiated from other cells and in most cases they ability to multiply have been curtailed. As a result, the depletion of the treated cells leads to high chances of the disease emerging again. Additionally, a patient may become allergic to the genetic therapy resulting to complications. While there are associated risks with any form of therapy, such risks must be measured against the accruing benefits. Such a consideration would determine whether genetic therapy is beneficial or otherwise.
Genetic therapy has been characterized by heated ethical debates, significantly in cases where germ-line genetic therapy is applied. The manipulation of reproductive cells in an attempt to modify the genetic makeup of offspring has been characterized as unethical and premised on interfering with natural processes. Meanwhile, after consideration of the benefits and drawbacks of germ-line genetic manipulation, it is evident that the drawbacks exceed the benefits by a significant margin; therefore, germ-line genetic therapy in relation to reproduction is prohibited. Given the successes of genetic research on the treatment of various genetic defects, there is a significant potential for genetic therapy being able to cure more advanced diseases such as cancer and heart diseases.