Gene Therapy - Restoring Sight

[Dark Angel]

The mongrels had a rare, inherited, genetic disease that causes nearly total blindness in puppies as well as human infants. There is no treatment now, but researchers at the University of Pennsylvania may be one step closer to a cure in humans with their study.

Humans with the disease could be good candidates for gene therapy because their photoreceptor cells -- which translate light into nerve impulses -- usually remain partially intact and responsive to therapy for some time after birth. In fact, recent studies have shown that cells in the retina may stay intact for many years -- even decades -- after the disease is diagnosed.

<a href="http://www.wired.com/news/medtech/0,1286,43262,00.html#">Full Story</a>

[Invincible]

Interesting indeed...medicine does miraculous things now a days. Who would have thought 'Gene Therapy?'?

[DuXcK]

Any idea how Gene therapy works ? <img src="/threads/images/graemlins/smile.gif" alt="" />

[Invincible]

No, enlighten me.

[Dark Angel]

Gene therapy involves fixing the actual DNA in cells. For this purpose, they use retrovirii. Retrovirii are amazing organisms in the sense that they hijack the cell's reproduction machinery. They insert their own genetic code into the cell's genetic code and so the cell is now converted into a virus production factory.

In gene therapy, they use a retrovirus, but they modify its genetic code so that it is no longer harmful. They splice in the gene they want to fix and inject the modified, safe virus into the person. The virus now infects the cell, but instead of destroying it, it fixes the bad gene.

[DuXcK]

very well summarized <img src="/threads/images/graemlins/smile.gif" alt="" />

How can we make sure that the Viral DNA wont contain any other DNQ sequences that can code for long term mutational changes ?

How can we make sure that the viruse infects the cells that we wanna fix only ?

Can gene therapy fix gross chromosomal abnormalities ?

[Dark Angel]

Thanks DuXck <img src="/threads/images/graemlins/smile.gif" alt="" />

Those are really good questions, but I guess we have to put our faith in the virologists and the geneticists. I believe they can identify the harmful parts of the viral DNA - the ones responsible for detrimental effects.

[Dark Angel]

As far as infection those cells that we want, I think each type of cell has a special type of surface protein. By calibrating the virus to attach to that particular cell, we can ensure that only those cells get fixed.

[DuXcK]

very true DA <img src="/threads/images/graemlins/smile.gif" alt="" />

The viruse used is specific for the cell trageted. These viruses usually bind to the cell by means of identifying a surface receptor, once the binding accurs, a process is insiatiated in which the viral DNA is swipped into the cell and travels into the nucleas where it get attached within the host's DNS.

If we are going to check the DNA content of all of our cells (those which contain a nuucleas of course), then, we'll see that the DNA content is complete in each and every cell !

The difference between different cells comes from the early differentiation process or by hormonal affects which either cause the expression or regression of some genetic codings.

If you insert a gene (lets gene XWX) into some host's DNA, then, the cell which got infected should have the capability to express that gene. If the viruse infected a cell which has nothing to do with the disease, then, we shouldnt have much of changes.

Now, I hope the above explained or simplified the reason or the mechanism in which Gene therapy can be specific.

as far as the coding is concerned, gene therapy is not an easy to use cause of the specifity of the treatement needed.

You have to make sure that you wont cause no hurm in order to be able to conduct any treatement.

Another point I'd like to bring: <b>If we correct a genetic disease in an affected individual, will his offspring's be cured too or he can transmitte the disease to his kids ? </b>

[Dark Angel]

Interesting question. For that, we have to target the sperm or the egg, or the sperm and egg production machinery... That would be really interesting.