Monday, 19 March 2012

Gene Therapy Treats Leber’s congenital amaurosis (LCA)



Using gene as a medicine is not impossible now!

Instead of using drugs, scientists and geneticists have discovered a new kind of treatment for some diseases by using genes as medicine - Gene therapy. There are several methods to correct defective genes such as incapacitate the faulty or particular genes. Another approach is introducing a new gene into body to fight disease. The other way is inserting adeno-associated virus (AAV) as vector to carry healthy genes and this technique can be applied to treat Leber’s congenital amaurosis as shown in figure 1.



                              Figure 1: Gene therapy (Diwan 2009)


Leber’s congenital amaurosis (LCA), a kind of blindness, is an inherited disorder influence nearly three thousand people in United States. In the past, Leber’s congenital amaurosis (LCA) was considered untreatable. Patients with Leber’s congenital amaurosis (LCA) normally have limited vision in their early childhood and further result in complete loss of eyesight after 3 or 4 decades.


A research has been done by gene-therapy researchers Maguire et al at the University of Pennsylvania. Scientists injected a harmless vector adeno-associated virus (AAV) which carry healthy gene into patients’ retinas by using a slim needle as shown in figure 2. After few weeks later, scientists test the patients’ responses to light. As a result, patients could detect three times more light (Kaiser 2008).


                                     Figure 2: A cure for congenital blindness (Mathiba 2011)


Apart from the study mentioned above, there is also a similar study at University College London. An 18-year-old patient with Leber’s congenital amaurosis has significant improvement in his vision after the injection. Before the treatment, he had difficulty to see things under poor light condition. The video below shows that his perception of light became much better after the treatment.


Video:




In conclusion, both results revealed that the ability to sense light have improved considerably. Originally, all the experiments mentioned above were primarily designed to test the safety. However, gene-therapy scholars accidently found that the experimental treatments are not only safe but also advantage to people with vision impairment.





References


Diwan, P 2009, ‘Gene therapy, hope of vision for LCA patients’, Topnews, 30 October, viewed 17 March 2012, http://www.topnews.in/gene-therapy-hope-vision-lca-patients-2230303 .
 
Kaiser, J 2008, ‘Gene Therapy Improves Sight of Four Patients’, ScienceNow, 28 April, viewed 16 March 2012, http://news.sciencemag.org/sciencenow/2008/04/28-02.html.

Maguire, AM et al. 2009, ‘Age-dependent eff ects of RPE65 gene therapy for Leber’s congenital amaurosis: a phase 1 dose-escalation trial’, The Lancet, vol. 374, no. 9701, pp. 1597-1605, viewed 15 March 2012, http://search.proquest.com.ezproxy.library.uq.edu.au/docview/199030184?accountid=14723.

Mathiba, N 2011, Gene Therapy, viewed 17 March 2012, http://nametsomathiba.blogspot.com.au/.
 
RP Fighting Blindness 2008, ‘Gene Therapy Improves Sight of 18 Year-Old Member’, RP Fighting Blindness, 27 April, viewed 16 March 2012, <http://www.rpfightingblindness.org.uk/newsevent.php?tln=newsevents&newseventid=28>.


1 comment:

  1. Hi Bio, My nephew is facing same problem. could you help me out.

    Can you focus me where I can find the doctor who treat this disease. OR email id? Looking forward

    My email id csahab@gmail.com

    ReplyDelete