Julia El Mecky & Lennart Johansson
Julia El Mecky is a medical anthropologist at the Clinical Ethics and Law group at the University of Southampton (CELS), United Kingdom, and at the department of genetics at the University Medical Centre Groningen (UMCG), The Netherlands. She is conducting her PhD research on uncertainty in genetic data.
Lennart Johansson is a postdoctoral researcher at the department of genetics at the University Medical Centre Groningen (UMCG), The Netherlands. He is part of the systems genetics unit with a focus on genetic analysis in rare disease. He earned his PhD degree in September 2019 on novel algorithms for variant detection in next-generation sequencing data. He also holds a BA in philosophy, which has contributed to his interest in the ethical aspects of genetic analysis.
Lennart Johansson is a postdoctoral researcher at the department of genetics at the University Medical Centre Groningen (UMCG), The Netherlands. He is part of the systems genetics unit with a focus on genetic analysis in rare disease. He earned his PhD degree in September 2019 on novel algorithms for variant detection in next-generation sequencing data. He also holds a BA in philosophy, which has contributed to his interest in the ethical aspects of genetic analysis.
Genetic uncertainty: Our changing understandings of genetic health data
The more we discover about the human genome, the more we understand how changes in its sequence influence our health and disease. For subjects who had their genome sequenced in the past, these updates might potentially lead to changes in their diagnosis as well as clinical management.
How should these changes be communicated, how often, and who is responsible for this? The authors of this paper in BMC Medical Genomics discuss the topic further in this blog post.
A case of genetic testing
Samila* had been suffering from shortness of breath and exhaustion when, at the age of 19, she was diagnosed with a heart that did not pump properly. Attempting to understand what caused this condition, her cardiologist suggested genetic testing. The test showed no underlying genetic factors for her heart issues and her medication was so effective that Samila thought it all might have been a fluke. However, when she was 26, her cardiologist unexpectedly contacted her with some upsetting information: part of her DNA had been identified as being involved in the development of dilated cardiomyopathy.
*Fictionalized case
Genetic testing: uncertainty amidst possible expectations of certainty
A genetic test inspects parts or even the entirety of the genome, which contains all our hereditary information encoded in the DNA.
The field of human genetics studies the workings of human genomes and how variations within it might play a role in the development of medical conditions. Through these studies, our genes can offer us important insights into why we have developed certain conditions, whether we could develop them in the future, and whether our children are at increased risk of developing them.
We frequently attribute a great deal of certainty to genetic testing and the information it produces in terms of what it can tell us regarding current and future health risks. However, for all our expectations, the connection between our genes and discuss our health is anything but clear-cut. The information provided by genetic testing often contains a multitude of uncertainties.
One such uncertainty is that the meaning of genetic information can change over time. Depending on the moment a genetic test is performed or its data interpreted, patients may receive different results. This can be unsettling for patients and pose a real challenge to genetic professionals.
Stable genomes, changing understandings
People change, their genomes do not. Our genome is inherited at conception and generally stays constant beyond the day we die. Patients like Samila may, therefore, wonder why they receive new genetic information many years later after their DNA was initially “cleared”. Despite its fixed nature, our understanding and interpretation of the genome is anything but stable.
Genetic testing enables us to inspect an individual genome for variations that differ from a template (i.e. ‘the’ human reference genome). Everyone has millions of variations that differ from this reference, but most are harmless or even beneficial. For patients, then, we need to establish whether these variations can explain or predict conditions or whether they are innocent.
In this sense, geneticists are kind of molecular detectives. They uncover evidence in order to ascertain whether their “suspects” – i.e. variations in an individual’s genome – are guilty or innocent regarding the development of specific conditions.
Complicating the task of reviewing evidence, like in an actual criminal investigation, is that new evidence might unfold as time passes. This new evidence may redefine how genetic variation might be involved in medical conditions.
In Samila’s case, for instance, it was uncertain if some of the initially identified genetic variation was harmless or suspicious. But as time went on, more patients with the same condition appeared to have this genetic variation, which indeed could be associated with cardiomyopathy.
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