8 Things You Should Know About Gene Therapy

Overview

Gene therapy is the treatment of a disease by altering, replacing, or supplementing a gene or part of the DNA chain that is responsible for said disease. The new DNA usually contains a functioning gene to replace the disease-causing gene.

1. There are two types of gene therapy. Somatic gene therapy is the transfer of a section of DNA to any cell of the body that does not produce sperm or eggs. Germline gene therapy is the transfer of a section of DNA to a sperm or egg-producing cell, which passes the DNA’s effect to subsequent generations.
2. There are several techniques for carrying out gene therapy, including gene augmentation therapy and gene inhibition therapy.
3. When a mutation of a gene causes disease, gene augmentation therapy adds DNA carrying a functional piece of the lost gene back into the cell. If the disease doesn’t damage the cell, the newly-introduced DNA can make a functional protein to replace the missing one.
4. Gene inhibition therapy is used to eliminate the activity of a gene that encourages the growth of disease related cells. Cancer is often caused by the over-activity of an oncogene; it can be stopped by inhibiting the activity of this gene.
5. How is the DNA supplied to cells? A section of DNA capable of making a useful protein is packaged within a vector, usually a virus, bacterium, or plasmid. Viruses are preferred as vectors because they have the unique ability to recognize certain cells and insert genetic material into them.
6. The vector carries the DNA to the patient’s cells; once inside the cell, the DNA is expressed by cells’ normal machinery and makes a therapeutic protein to cure the diseased cells. To be successful, a vector must target the right cells and integrate the gene in cells, activate the gene to create the protein product it encodes, and avoid harmful side effects.
7. Researchers have transplanted genes into the brain using liposomes coated with polyethelyne glycol; the transfer of genes into the brain is a significant achievement that has potential to treat Parkinson’s disease.
8. Gene therapy’s potential to revolutionize medicine in the future is exciting and hopes are high for its role in curing and preventing genetic disorders like cystic fibrosis, sickle cell anemia, thalassemia, and familial hypercholesterolemia in children.

Further Reading

Mavilio, F.; Ferrari G. (2008). Genetic modification of somatic stem cells. The progress, problems and prospects of a new therapeutic technology. EMBO Rep. 9 Suppl 1:S64–9.

Woods, N.B.; Bottero, V.; Schmidt,M.; Von Kalle, C.; Verma, I.M. (2006). Gene therapy: Therapeutic gene causing lymphoma. Nature 440 (7088) 1123.

Cavazzana-Calvo, M.; Thrasher, A.; Mavilio, F.(2004).The future of gene therapy. Nature 427 (6977) 779–781.

Picture Credit

BBC UK. http://www.bbc.com/news/health-23269778.