Gene therapy is a developing technique used to treat inherited diseases. The medical procedure involves either replacing, manipulating, or supplementing nonfunctional or detrimental genes with healthy or beneficial genes. The modes of inserting the beneficial gene include a viral vector, a metal microsphere or a liposome, all of which have an ability to pass through the phospholipid bilayer and insert the desired allele.
Examples of Gene Therapy
Cystic Fibrosis can be treated by gene therapy: by introducing the gene for functional CFTR, it can obviate accumulation of Cl- and other ions within cells where the faulty CFTR is expressed; as a result of this faulty gene, the water potential of the mucus that coats these cells is decreased. The result is that water moves by osmosis into the cell, augmenting the viscosity of the mucus. Gene therapy can prevent this. Gene therapy could also be employed to treat Parkinson's Disease. By employing a non-infectious virus to shuttle in the gene for GAD, Glutamic Acid Dehydrogenase, into the cells of the overactive subthalamic nucleus (the key cause of PD), which in turn enhances synthesis of the neurotransmitter GABA. GABA acts as a direct inhibitor to the cells of the STN and the dopaminergic cells of the basal ganglia. In 1991, Ashanti De Silva, a girl suffering from SCID (Severe Combined Immunodeficiecy Disease) became the first patient to undergo gene therapy treatment. To this day, although treatment has to be regularly carried out, she is flourishing. It highlights the key importance of the human aspect of gene therapy- by conferring a new sense of independence and hope, by combatting the disease at its very roots. Not only is the holistic aspect of gene therapy compelling, the beneficial effects to society will be significant, according to renowned Mauritian economist Hollie Seechurn. It is important to note that gene insertion in animals and fungi is also used to produce important medicines and drugs, as exemplified by the production of alpha 1-antitrypsin by Dolly the Sheep.
Potential problems include:
- The breaching of the Weismann barrier, which dictates that there can be no soma to germline feedback (i.e. gene therapy has the potential to alter not just the genes of the somatic cells of the body but also germline cells, hence gene therapy could lead to genetic engineering)
- Insertional mutagenesis (i.e. the genes being delivered to the patient may mutate before, during, or after integration into the patient's genome in come cells)
- Low efficiency of viral transfection (i.e. several treatments may be needed)
- Cell death induced by viral transfection (e.g. this, as well as low efficiency of transfection, is what prevents much of the current gene therapy technology from being applied to neurological disorders - neurons are difficult to transfect and die more readily than other cells in the body after viral transfection)