Genes are the part of DNA molecule. They are the source of providing information for making an organism whether it is a human or any other animal and plant. Chromosomes are the structures in the human body cells that contain different kinds of genes. Every gene or set of genes have variety of functions to perform that is why they have different set of information in them. When a child is born, he has two set of genes, one set from his mother and one from his father. These genes are complementary to each other and this make the new human being. Genes have the ability to turn off and on depending on where they are needed. For example, some genes are involved in the making of heart, so they are on for that part and anywhere else, they are turned off. Some genes are involved in determining the color of the eyes of a person and some are even involved in creating various genetic diseases in humans. Before explaining the procedure of gene therapy, it is necessary to have a look at genetic diseases that how they are produced.
As described earlier, some genes give different colors to the eyes. For example, red, green, blue and black colors produce due to the variations in the genes. It all occurs due to the evolution which occurs in human body. But some genes, as a result of evolution, are harmful and those genes are reason of causing genetic illnesses in human body for example the disease of hemophilia. But some genes are the source of causing genetic diseases because of the environmental factors. For example, diabetes is caused in people due to the lack of nutrition and lack of exercise. Some genetic diseases can protect the person from having other harmful diseases such as sickle cell anemia if caused in a person and he gets this disease from only one parent mother or father then there are bright chances that the person will be protected from the disease of malaria. Now readers can easily understand the process of gene therapy.
Gene therapy is one of the many techniques of biotechnology that is used to detect genes which cause diseases in organisms. It tries to fix the problem by altering the defected gene with the normal one. Though this gene therapy is a very useful technique but it is quite difficult to detect the disease causing genes and even if they are detected, they are difficult to remove or repair. For example some genes are broken that is why they cause the disease and let it flourish, scientists repair the broken parts and genes start working in the normal way. Some genes are aggressive, so they are required to be removed from the cells and new genes will be introduced in those cells. Some genetic diseases are caused by multiple genes and there is a bad thing is that this last error is the source of most of the genetic diseases. Gene therapy can be preceded by making corrections in the faulty genes but there is another point is that that changes are made in the germline cells so that the problem of occurring the genetic disease can be fixed before it inherits in the child. Though this technique is very useful and beneficial but it has some limitations and is not very successful yet. New genes are extracted from viruses but then there arises the problem of other infections through viruses. May be person's immune system does not accept these changes in the genes or the DNA in which genes are inserted do not work properly. The first genetic disease which was cured by using the technique of gene therapy was ADA Severe Combined Immune deficiency. In this type of disease, the patient is put in a bubble because his immune system is so weak that he cannot live like normal people except if they get bone marrow transplantation. This disease is also called as bubble boy disease. Gene therapy technique was performed in Italy in which scientists inserted a therapeutic gene called ADA in the bone marrow cells of the patient in the laboratory. They transplanted the cells which were already corrected. Now those children are living a normal life with their families.
There is another disease which is genetic is the disease of hemophilia. In this disease, person's genes cannot make the clots of the blood after that person gets cut by a knife or any other sharp thing. External and internal bleeding can also occur depending on the condition of the injuries. This disease can be fatal also. Scientists used the technique of gene therapy and a therapeutic gene was inserted into the liver cells. It gave good results and blood started making clots. But there was a side effect also that is the immune system of the person refused to accept that gene. Same problem occurs when people undergo organ transplantation.
Many other genetic disorders are also corrected by gene therapy. Some diseases other than genetic diseases can also be corrected with gene therapy. For example in the cancer disease, patients are treated with multiple genes and therapeutic gene vaccines. Neurodegenerative and other acquired disease can also be treated with gene therapy and give healthy results.
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