New Gene Therapy

Here's another interesting one:

http://www.betterhum...17/Default.aspx

They say their technique allowed them to cure phenylketonuria in lab rats in 3 injections. That sounds pretty amazing. What are then the limitations on this technique?

Are there some genetic diseases it wouldn't work on?

It says it inserts at specific sites, so does that impose any constraints? Can it only insert a single gene?

A very significant discovery. Finally the safe location to insert new DNA in (a non-coding rare DNA sequence). As the author has mentioned, the technology challenge is how to deliver the DNA in situ.

PKU is a singe gene disorder so the technique should work for all types of single gene disorders. In fact this technique could be used to deliver therapeutic doses of any type of endogenously produced substance including supplementing declining levels of hormones, repair factors, immune modulators, etc. The take home point is that in contrast with previous attempts of DNA recombination which were random, a safe genomic location and method for the therapeutic DNA to be inserted in has been discovered. In previous studies some newly inserted DNA was localizing to regions of the chromosome that resulted in oncogene activation/tumor suppressor deactivation.

Yep - this system has incredible potential. It was one of the few big new things I tried but failed to feature at SENS2 - Woo had a prior commitment and Chen (who is a Chinese citizen) had some sort of visa-related showstopper. See also the work of Michele Calos at Stanford, who has been pioneering this approach.

By the way - am I right in saying that the paper is not in this week's PNAS at all? If it isn't, that's the secnd time this year that a PNAS paper of interest to me has been the subject of a press release a week early... weird.

There are other approaches to targeted gene therapy around, of course (see SENS2 session 2), all quite early-stage though except the adeno-associated virus which has the big problem of only being able to carry a few kb of DNA.

The main limitations are to do with insertion efficiency, i.e. the number of cells that get the DNA. PKU is a very easy target in this respect because even if only a few liver cells get mended they will rapidly proliferate while the un-fixed ones do not.

Does anyone of you have a link to a real paper about this success?