Gene Therapy

Gene Therapy

Gene therapy involves utilizing DNA as a pharmaceutical tool to address diseases. Its concept revolves around the notion that DNA can be employed to either supplement or modify genes within the cells of an individual as a means of treating ailments. The most prevalent approach to gene therapy entails utilizing DNA encoding a functional, therapeutic gene to replace a defective gene.

Other methods involve directly rectifying a mutation or employing DNA encoding a therapeutic protein drug, rather than a natural human gene, for treatment. In gene therapy, the DNA carrying the therapeutic protein is encapsulated within a "vector," which facilitates the delivery of the DNA into cells within the body. Once inside, the DNA is expressed by the cellular machinery, resulting in the production of the therapeutic protein, thereby treating the patient's condition.

Researchers have endeavored to introduce genes directly into human cells, focusing on diseases caused by single-gene defects such as cystic fibrosis, hemophilia, muscular dystrophy, and sickle cell anemia. However, this has proven to be more challenging than modifying bacteria, primarily due to the complexities associated with transporting large segments of DNA and delivering them to the precise site on the gene.

Presently, most gene therapy investigations target cancer and hereditary diseases associated with genetic abnormalities. While antisense therapy is not strictly considered gene therapy, it is a related genetically-mediated therapeutic approach.

The predominant method of genetic engineering entails inserting a functional gene into an unspecified location in the host genome. This involves isolating and replicating the gene of interest, creating a construct containing all the necessary genetic components for proper expression, and subsequently integrating this construct into a random location in the host organism. Other techniques of genetic engineering encompass gene targeting and the elimination of specific genes using engineered nucleases such as zinc finger nucleases, engineered I-CreI homing endonucleases, or nucleases derived from TAL effectors. An illustration of gene-knockout mediated gene therapy is the elimination of the human CCR5 gene in T-cells to manage HIV infection, a method currently undergoing several human clinical trials.

Gene therapy can be categorized into two main types:

1. Somatic gene therapy

In somatic gene therapy, therapeutic genes are introduced into the somatic cells or the body of a patient. Any alterations and effects are confined to the individual patient and are not inherited by subsequent generations. Somatic gene therapy constitutes the primary focus of current basic and clinical research, utilizing mRNA to address diseases in individuals.

2. Germ line gene therapy

Germ line gene therapy involves modifying germ cells, namely sperm or eggs, by introducing functional genes that become integrated into their genomes. This approach allows the therapy to be heritable and passed on to future generations. Despite its potential effectiveness in combating genetic disorders and hereditary diseases, many jurisdictions presently prohibit its application in humans due to various technical and ethical considerations.