Science Questions

Do genes delivered by gene therapy get inherited?

Wed, 14th Mar 2012

Listen Now    Download as mp3 from the show Genes and evolution - from populations to tumours

Question

Ian McKay asked:

Hello Naked Scientists!

 

After an individual receives a treatment of gene therapy, is it the original faulty DNA, or the new corrected DNA, that gets passed on to their offspring? Is it only males that can pass on the new gene, because female eggs are not "updated"?

 

Thanks!

 

Ian McKay

PhD Student

Cornell University

Answer

Most types of gene therapy are what’s called somatic gene therapy - they’re designed to only deliver genes to certain non-reproductive cells of the body, such as delivering a healthy version of the damaged cystic fibrosis gene only to the lung cells of someone with the disease. This is the main approach being used by scientists working in gene therapy. It’s very unlikely that these genes could transfer into the sperm-producing cells in men, and even less likely they could get into the egg cells in women. Germline gene therapy, which changes the genes in sperm or eggs so they would be passed on to children, is actually banned in most parts of the world at the moment, for both technical and ethical reasons.

Multimedia

Subscribe Free

Related Content

Comments

Make a comment

Ian McKay asked the Naked Scientists: Hello Naked Scientists! After an individual receives a treatment of gene therapy, is it the original faulty DNA, or the new corrected DNA, that gets passed on to their offspring? Is it only males that can pass on the new gene, because female eggs are not "updated"? Thanks! Ian McKay PhD Student Cornell University What do you think? Ian McKay , Sat, 30th Apr 2011

Just to clarify a bit (since the above interpretation of my second question seem to just assume that the answer to the first is "corrected DNA"), what I asked was:

"I have a quick question related to the gene therapies that you discussed on the last episode (amazing stuff!). As I understand it, a virus is used to deliver a correction to the actual DNA in the target cells. So my question is this: after an individual receives this treatment, will the original faulty DNA, or the new corrected DNA, be what is (potentially) copied to their offspring? If the new, then is it only the new for males, or also for females (since I don't see how their eggs would be "updated")?"

I love the show Naked Scientists! I listen every week--great work!! ijm, Sun, 1st May 2011

hi Ian

good question. In answering this question it's critical to distinguish between what are referred to as changes to the germ line and changes to somatic DNA. The germ line refers to the cells and their progeny that make gametes (sperm and eggs). Somatic DNA is the genome carried within the other (non-germline) cells around the body.

Genetic diseases usually affect a target tissue, and genetic therapies are usually designed to remedy the genetic defect within that target. For instance, in cystic fibrosis the lungs (as well as the gut and other tissues) are affected. Gene therapy would aim to augment the genetic repertoire of the affected lung cells, restoring normal function. But the sex cells would not be targeted by the therapy and hence the gametes of the affected individual would still be capable of conveying the condition to a subsequent generation.

If, on the other hand, genetic manipulations were made to an individual early in development while they were at the stem cell stage, meaning that the manipulations would be passed into the cells that will become the sex cells (gonads), then not only would the body cells be transduced with the new gene, but so would the gonads and hence the changes would be heritable.

This is in fact how researchers make transgenic animals.

Such practices are not carried out medically, however, on ethical grounds owing to objections about "playing God", as well as potential unforeseen risks associated with such a manipulation.

Instead, some parents identified as carriers of genetic conditions elect to pursue PGD - preimplantation genetic diagnosis - to screen out embryos destined to develop a disease because they have inherited an abnormal gene from an affected parent. Instead embryos deemed healthy are implanted using IVF techniques.

Chris chris, Mon, 2nd May 2011

Thank you very much for the reply, Chris! ijm, Tue, 3rd May 2011

See the whole discussion | Make a comment

Not working please enable javascript
EPSRC
Powered by UKfast
STFC
Genetics Society
ipDTL