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Biotechnology

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Gene therapy – hope for the future?

There are a number of genetic diseases which we now know are caused by a defect at a single gene locus. These diseases include haemophilia A, cystic fibrosis, Duchenne muscular dystrophy, sickle cell disease, Huntington’s disease and SCID (severe combined immunodeficiency). Gene therapy offers the hope of introducing healthy genes into the cells of people affected by the diseases, enabling them to function normally and restoring the patient to health. New technologies such as CRISPR-Cas9 are making it easier for scientists to manipulate the genome accurately and safely.

One of the first diseases targeted for gene therapy was cystic fibrosis (CF). For a considerable time, success was very limited. However, from 2015, results have been more promising. Researchers are using different approaches to carry the healthy genes into the lung cells of affected patients. Some are using viruses, some are using lipid bubbles. In 2015, one group recorded lung function in a group of patients treated by gene therapy as 3.7% better than the placebo group. This isn’t much, but for patients with CF, every little bit makes a real difference. 2017 sees the start of a new round of human trials using different, and hopefully more effective, vectors to transmit healthy genes into the lungs of CF patients.

There are a number of trials showing real promise in using gene therapy to treat some of the many forms of inherited blindness. Another disease where gene therapy showed great initial promise was in the treatment of severe combined immunodeficiency (SCID). Major problems arose, with some patients developing leukaemia – but scientists and doctors persisted and now there are continuing clinical trials of versions of gene therapy for SCID which are showing promise in both infants and older children.

In 2017, scientists announced the successful treatment of a teenage boy who was severely affected by the genetic disorder sickle cell disease. Doctors removed some of his bone marrow, added new genes to the cells to code for healthy beta-globin, and then replaced the bone marrow. Fifteen months later the cells are still making healthy haemoglobin and the boy is free from symptoms.

 

For more information, check out the following content in our Genetic engineering resource:

Sickled red blood cells don’t carry oxygen effectively and block blood vessels causing pain and tissue death. Genetic modification of the blood stem cells may eventually make this disease a thing of the past.

Discussion point

There are many ethical questions about using such new and experimental techniques on patients who are already very sick. Here are two pairs of commonly expressed opinions, one in favour of treatments such as gene therapy and one against. Use the resources listed below – and any others you chose to use – to find out more about gene therapy and the progress made so far. Then from each pair of statements chose the one closest to your own viewpoint. Write one or two paragraphs expressing your opinion, putting forward the main arguments for and against the idea and justifying your position.

 


A:

 

 

  • Gene therapy shouldn't be used on humans until scientists are sure it works.

  • It is worth trying out a new therapy which may give a person some extra healthy time if they are going to die or have a very poor quality of life without the treatment.


B:

 

 

  • Manipulating the genes is wrong – it's interfering with nature.

  • Medicine only progresses by trying out new treatments, even if the early patients die. Look at what happened with heart transplants!


Emily's view

The benefits of gene therapy

"I don't think there is any problem with doing research into gene therapy. The scientists tell us that it could cure loads of diseases and that can only be a good thing. I mean, if I'd found that there was something wrong with me then I would want to get it sorted out. If that means getting someone else's genes that would be fine, if they were working properly and solved the problem. I know some people think it would be like making new mutants or something but I think the scientists know what they're doing. And anyhow, there are laws to stop them doing anything dangerous. I think it's a good thing."

Priyanka's view

Concerns about gene therapy

"I'm not sure about all this genetic engineering and gene therapy stuff. I'm not sure if it should be allowed or not. I think it's worth trying out new treatments if they could help people in the future. Especially if it means they get to live longer, or if they have a very poor quality of life without the treatment. I think there's still a lot of research needed to be done before scientists can be sure it's completely safe for humans. But then, medicine only progresses by trying new treatments, even if the early patients die. That's what happened with heart transplants and look at how many lives they save now. I'm not completely convinced. I mean, gene therapy is manipulating genes and is a bit like interfering with nature. And I'm not sure that is the right thing to do."