gene therapy
the insertion of segments of healthy DNA into human body cells to correct defective segments responsible for disease development. A carrier molecule (vector) is used to deliver the therapeutic gene to the patient’s target cells, restoring them to a normal state of producing properly functioning proteins. The most common vector is a virus that has been specifically altered to carry normal human DNA, but several nonviral options are being explored as well. Though experimental, current gene therapy holds significant promise as an effective treatment for a variety of pathological conditions, including neurodegenerative disorders. It is not, however, without its share of challenges and limitations: (a) difficulties integrating therapeutic DNA into the genome and the rapidly dividing nature of many cells have prevented any long-term benefits; (b) if the body’s immune system response to foreign objects is triggered, benefits of the therapy may be
mitigated; and (c) conditions that arise from mutations in a single gene are the best candidates for gene therapy, yet some of the most commonly occurring disorders (e.g., heart disease, high blood pressure, Alzheimer’s disease, arthritis, diabetes) are caused by the combined effects of variations in many genes. There are also ethical, legal, and social concerns associated with the practice. See also genetic engineering.