1. SECTIONS:
2. preface & acknowledgements
3. genetics at a glance
4. contacts, support & testing
5. testing & pregnancy
6. newborn screening
7. cancer in the family
8. cardiovascular conditions
9. chromosomal conditions
10. clotting & bleeding conditions
11. cystic fibrosis
12. diabetes
13. fragile X syndrome and other causes of developmental delay
14. haemoglobinopathies
15. hereditary haemochromatosis
16. neurofibromatosis
17. neurological conditions
18. psychiatric conditions
19. genetics in practice
20. emerging genetic technologies
21. glossary

Gene Therapy

 

1. Gene therapy involves the introduction of new genes into targeted cells of the patient’s body. It is highly experimental, but has the potential to treat and cure inherited or acquired genetic conditions that are currently incurable.
2. New genes can be introduced into human cells either in vivo or in vitro.
3. The new gene can be inserted into a patient’s cells in vitro and the modified cells are then transplanted back into the patient.
4. Genes that will modify the immune response to infectious disease or cancer can be targeted to a patient’s immune system (eg lymphocytes).
5. There are two main methods of delivering therapeutic genes into a patient’s cells:
6. Viral delivery: the use of a modified virus that contains the desired gene yet does not cause an
   infection. As viruses work by inserting their genes into the host’s cells, viruses can be genetically
   manipulated to deliver therapeutic genes directly into a patient’s cells – sometimes being targeted at a particular organ or cell type
7. Non-viral delivery: the creation of nanoparticles, containing the therapeutic gene, so small they can be transported by the bloodstream and absorbed by target cells.

 

Applications

1. Conditions targeted in Australian gene therapy trials include cancer, cystic fibrosis, haemophilia and HIV/AIDS.
2. One gene therapy that has been approved for routine treatment is for squamous cell carcinoma, which was approved in China in early 2004. In this treatment a tumour suppressor gene is introduced into patient’s cells using a modified viral vector.
3. There have been growing concerns regarding the safety of gene therapy vectors. The high efficiency of random integration into the host’s DNA has always been perceived to have a hypothetical risk for mutagenesis.
4. The use of gene therapy in the treatment of severe combined immune deficiency (SCID) by a French research group (Cavazzana-Calvo M et al) was hailed as the first example of a genetic condition being successfully treated by gene therapy.
5. Seven out of ten infants treated to date have restored immune function. However two of the children treated initially developed leukaemia in 2002 and 2003, caused when the virus used to deliver the therapeutic gene activated a cancer-causing gene (oncogene).
6. The clinical trials were halted but have now been resumed only for patients with no other treatment options.
7. This experience illustrates the need for this therapy to be conducted as part of clinical trials.

 

Ethical issues

1. Beyond its medical applications, concerns have been raised that gene therapy could be used for superficial reasons, such as enhancing athletic ability.
2. The potential cost of gene therapy is also a matter of concern if it places too great a burden on health care systems or is only available to those who can afford it.
3. Additionally, the possible genetic manipulation of the egg or sperm cells (germ line gene therapy) remains the subject of intense ethical and philosophical discussion.

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