Is Knowledge Always Power? – Genetic Testing

DNA_Double_Helix

No, I’m not talking about intelligence being the key to power and success (that’s a different story altogether). I’m talking about the power we gain from our knowledge of genetic causes of disease. Imagine a time when we can all be genetically tested to find out if we have the version of a gene (allele) which is known to cause a certain disease. When I say this, mean an allele which is definitely the cause of a disease; at this point, I’m not talking about a frail link or something which can make us more predisposed to an illness. Now, imagine being told that you have a gene which causes a certain disease, and that at some point in the future – the doctors can’t tell you exactly when – you’ll start showing symptoms, and one day, it will kill you. The disease is fatal. There’s no cure for it. Is this knowledge going to make you feel better, “to be forewarned is to be forearmed”, or does it make you worse, knowing that one day, this gene is going to be the cause of your death? Or if you were told you were predisposed to a certain illness – that means you have a higher than usual chance of developing it – there would be so much anxiety accompanied by this knowledge, which isn’t even concrete evidence that you will have the disease. Would you rather live in ignorance, by choosing not to know, until the disease does or doesn’t affect you, or would you rather find out and cope with the worry that accompanies this knowledge?

A story that’s stuck in my mind since I read it, is one which I came across in the book, Genome, by Matt Ridley. A study was carried out by a woman named Nancy Wexler, in search of the gene which causes Huntington’s disease. This study was carried out on the shores of Lake Maracaibo, west of Venezuela, an area containing a large family with a high incidence of Huntington’s Disease. Doctors tested people in the area for neurological signs of the disease, before individuals had noticed any symptoms themselves. After the tests were performed, most people did not ask for the results, for one reason or another, but one woman in particular asked the doctors if she had the disease. The doctors tiptoed around the question, by asking her what she thought, to which she replied that she thought she was ok. They explained that they could not give a definite diagnosis, and that they would need to know her better, avoiding answering her question. The woman had in fact shown early signs which suggested she had the disease. Afterwards, a friend of the woman rushed to the doctors, asking what they had told her. The doctors explained what they had previously said, and the woman’s friend was relieved. She explained that the woman they had just seen intended to commit suicide immediately if she found out she had the disease.

Were the doctors right not to tell the woman that she had Huntington’s disease? Let’s bear in mind that no cure was offered, and there still is no cure, more than thirty years on. Is it wrong to give false hope to someone that will eventually die from a disease? The woman may have had several more years ahead of her, without showing any symptoms, so without the knowledge, she could have these years of happiness and ignorance ahead of her, until the disease begins to have an effect.  Surely knowing that this incurable disease would strike at any point could only have a negative impact on her mental health. It’s like giving someone a death sentence, but not giving them a date. But at the same time, didn’t she deserve the right to know, and to be able to do with this information whatever she wants?

All this talk in recent years of maybe one day being able to genetically screen us all for certain heritable diseases, or certain predispositions, comes with a huge moral weight. Finding that a person holds a genetic mutation which causes something which we can cure is obviously incredibly useful; if we can detect it, we can treat it early and this usually gives a greater chance of survival. Detecting genetic mutations that cause illnesses which we cannot cure however, may not directly help the affected individual as much as we would like. There is no use in telling someone that they will one day develop an illness if we aren’t going to do anything about it. Before we truly look into this kind of futuristic genetic technology, we need to think long and hard about how freely we want to give out this life-changing information, and how we are going to help those who are affected.

Babies have blood taken from the heel of their foot to test for inborn errors of metabolism.
Babies have blood taken from the heel of their foot to test for inborn errors of metabolism.

In terms of finding out that someone has a predisposition towards a certain illness, such as heart disease, early detection can help by letting us cut down on other risk factors, so we can work to prevent them from developing the disease. Genetic testing is already available to find out if an individual has a genetic mutation which causes an illness which runs in their family; this is used to test parents to find out if they are carriers of a disease before they have a child, to test newborn babies and to test people who know that a genetic condition runs in their family. For example, Angelina Jolie had a double mastectomy in 2013 to reduce her chance of developing breast cancer, as she carries a gene called BRCA1, which increases an individual’s lifetime chance of breast cancer to over 80%. In cases such as this, and prenatal screening, the advantage is clear (although ethical questions always exist, particularly in prenatal screening of embryos). However, not everyone who knows a condition runs in their family chooses to have a genetic test. Some people prefer just not to know.

Particularly when it comes to something which we do not have a cure for, we must use this information or else it is no help at all: counselling strategies and treatments are needed to help manage symptoms for those affected (we are already doing this to manage symptoms in those who have an incurable illness, though a lot more would be required if we decide to do this more widely). I am hugely in favour of genetic testing being able to be offered to those who want it (the key word there being want) who believe they may be at risk from a certain hereditary condition and in favour of progressing genetics and medical diagnostic techniques in general, but there are considerations to be made. There are clear advantages to prenatal screening, testing babies for inborn errors of metabolism and early diagnosis for diseases which we can offer cures and treatments for. It’s cases like the woman in the story I told earlier that worry me. A diagnosis is only useful when paired with some form of treatment, whether in the form of counselling, or treatments for management of symptoms. Knowledge is only power if we intend to do something about it.

If you want to learn more about how and when genetic testing can be done, the NHS website has some useful resources: Genetic Testing And Counselling.

What do you think about genetic testing? When should it be done and is it always worth it?

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