Gene therapy refers to a technique in which a healthy DNA is inserted in a person’s cells in order to cure a disease or to replace a mutated gene. Either a healthy gene is inserted directly or a gene encoding for a therapeutic protein is used.
In Preventive Gene therapy, a gene is inserted at a young age before the defected gene is expressed. A DNA carrier or a vector is used to transfer the new DNA in the body, these vectors can be viruses or a non-viral method like insertion of naked DNA and electroporation can be used.
Gene therapy is being considered as a potential cure for cystic fibrosis. This therapy puts a normal copy of membrane protein known as cystic fibrosis transmembrane conductance regulator gene (CFTR) into the affected epithelium cells which then would result yielding of functional CFTR in all the targeted cells. Also just adding 5 to 10 percent of CFTC has been shown to prevent the lung manifestation of cystic fibrosis.
Generally, treatment of severe combined immunodeficiency (SCID) is done by bone marrow transplantation, but recently, gene therapy has been attempted as an alternative means of treatment for SCID. This therapy involves isolation of white blood cells and insertion of a healthy adenosine deaminase (ADA) gene using a retrovirus into the while blood cells, which then the mixed cells are injected back into the body and begin to express a normal enzyme. This way, gene therapy can be used for the treatment for both type of SCID disorder – ADA-SCID and X-SCID.
Similarly, gene therapy has also been shown effective for the treatment of Parkinson’s disease, Myeloma and Leukemia.
Most of the genetic disorders cured by the gene therapy are caused by one mutated gene, as those with multiple mutated genes are still very difficult to cure even with the latest techniques of gene therapy. Although gene therapy has a tremendous potential for good, it has a very limited use due to the disadvantages associated with the process right now.
Our immune system attacks any invader it detects and destroys it, so making sure that the DNA would reach its required site in the cell becomes very difficult.
Another disadvantage is the short term activated DNA or genes. For a disease to be cured completely, the inserted DNA must stay activated for a long times, which doesn’t happen in most of the cases, means a person would need multiple rounds of therapy before seeing any significant improvement.
The vector or the viral particles also pose danger to human body, as they can regain their virulence and result in serious viral infections and may also lead to toxification. Beside that, the inserted DNA can easily get damaged or mutated during rapid cell division and can cause cancer.
However, despite all the disadvantages, gene therapy will soon become a reality making life disease free by helping scientists discover new ways to come up with regenerative medicines to defeat cancer, AIDS, diabetes and other dreadful ailments.