About Gene Therapy

Gene therapy is a technique that uses gene to treat or prevent certain disease. There are several approaches in gene therapy including replacing a mutated gene that causes disease with a healthy copy of a gene. Besides that, inactivating or "knocking out" a mutated gene that is functioning improperly. Moreover, introducing a new gene into the body to help fight a disease. This technique may allow doctors to treat a disorder by inserting a gene into a patients cells instead of using drug or surgery. This technique remain risky and is under study to make sure that it will be safe and effective. Generally, gene therapy could be divided into two types which are somatic gene therapy and germline gene therapy. The somatic gene therapy would introduce a normal gene into the targeted cells for treatment. The gene also will be not passed to the next generation thus the patients offspring still have a chance to face the same disease. The germline gene therapy will modify the gene in the reproductive cells. The altered gene will be passed on to the next generation. This technique could treat certain growth and fertility problems and one of the potential technique to prevent the inherited disease.

if a mutated gene causes a necessary protein to be faulty or missing, gene therapy may be able to be use as treatment. A normal copy of the gene may be introduce to restore the function of the protein. The normal copy of the gene cannot be directly inserted in patient body. thus, a carrier called a vector is introduced to carry the normal gene into the affected gene. Vectors are carrier molecules which are employed to enhance gene transfer efficiency in gene therapy. Choosing the right vector might have a high chance by considering host immune respond, the target specific tissues for long term gene expression and regulation of gene after insertion. There are two types of vector which are viral vector and non-viral vector. The most common viral vectors are retrovirus, adenovirus, adeno-associated viruses and herpes simplex viruses. Non-viral vector are cationic liposomes, injection of naked DNA and by using chemical methods to enhance gene delivery.

Figure 1: The picture credit to U.S. National Library of Medicine

There are also issues that rises up in gene therapy because this gene therapy make changes of the body's basic instruction. several example of question that are arise such "how can good and bad uses of the gene therapy be distinguished?", "who decides which traits are normal and which constitute a disability of disorder?", "will the high costs of gene therapy make it available only to the wealthy people?" and "should people be allowed to use gene therapy make society less accepting of people who are different?". Germline gene therapy is controversial issue. Although it could spare future generation in a family from having a particular genetic disorder, it might affect the development of a fetus in unexpected ways of have long-term side effects that might lead to a new disease.