Science Week: Making sense of medical genetics

This post was contributed by Dr Clare Sansom, of Birkbeck’s Department of Biological Sciences.

Professor Nick Keep (left) and Professor Jonathan Smith (right)

Professor Nick Keep (left) and Professor Jonathan Smith (right). Photo: Harish Patel

Genomics is still quite a young science. It is scarcely a decade since the first human genome sequence was decoded, at a cost of $3 billion, and we are already discussing the implications of the $1,000 or even $100 genome. Accurate genetic testing is now available for a wide range of diseases and conditions. And it is perhaps not surprising that we find it difficult to deal with this barrage of information, particularly when it comes to how it affects our own health.In the last of the 2013 Science Week lectures, Professor Jonathan A Smith, from Birkbeck’s Department of Psychological Sciences, described how people at risk of genetic disorders made decisions about testing, and how they responded to test results: thus, how they made sense of the personal implications of the complex discipline of medical genetics. His approach to his discipline is qualitative rather than quantitative: the case studies he reported involved in-depth discussions with a small number of participants rather than questionnaire evidence from large cohorts. Using this, he has been able to gain considerable insights into the thought processes involved in complex, personal and ethical decision making. Furthermore, he stressed, his is a two-way approach: he as the researcher is in some sense in a similar position to his participants in attempting to make sense of their genetic stories. At the same time, he is also in a different position from the participants as his sense-making is always of an account that they provide.

Genetic testing
In his lecture on 18 April, Professor Smith began by explaining the process that is involved in clinical genetic testing. Generally, an individual with a family history that indicates that he or she may be at risk for a condition will approach a clinic directly to be tested. There, the specialist will take a complete family history and explain the genetics of the condition, the possible spectrum of risks involved and what the results may mean. Whether the test goes ahead will be the client’s (or patient’s) own decision and that decision is very rarely a straightforward one. Test results will move the individual tested from a broad risk category into a narrower one and, in a few cases, that narrow risk category will be a 0 per cent  or 100 per cent risk of the disease. That individual risk, however, may not be the only result; very often, a test result for one individual will mean changes in risk category for some of his or her blood relatives. These relatives may not want to take the test, or they may lack the capacity to decide for themselves (if, for example, they are children). And once a test is taken, the knowledge obtained cannot be un-learned: there is no way to put the genie back in the bottle. 

Huntington’s disease
Huntington’s disease is one of the most devastating of all genetic conditions. It is a fatal, progressive neurological disorder with an onset at any age between the 30s and the 60s, so many  patients will already have children before they are diagnosed. All people who inherit one copy of the faulty gene will eventually develop the condition, although it is impossible to tell when, and a child with one parent with the disease is at 50 per cent risk of developing it. A genetic test is available that will either reduce that risk to zero or increase it to 100 per cent.

Professor Smith presented the results of a study of decision-making in people at risk of Huntington’s disease using a technique known, in the jargon, as interpretative phenomenological analysis. The investigators spoke in depth to a small number of participants, used no fixed questions, and aimed to let the participants tell their own stories. In this particular case, all these had one parent diagnosed with Huntington’s disease and so were at 50 per cent risk of the disease before testing; and each of them already had children of their own. He described the very different thought processes and reasons that three of these individuals brought to their decisions – two were in favour of taking the test, and one was inclined to not take the test.

One thing united these three individuals (and by implication the other participants whom they in some sense represented): the desire to “do the right thing by their children”. Professor Smith presented this as a case of a classic moral dilemma, where no one strategy should be seen as right or wrong, and suggested that the case studies would help genetic counsellors to understand the range of emotions and responses that is likely to be experienced by their clients.



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