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Prof. Conny van Ravenswaaij-Arts: ‘Incidental findings in genetic testing call for strict national guidelines’

23 May 2012

The developments in genetics are rapid. It has recently become possible, for example, to study all the hereditary information of a patient in a single test. But what should you do with the incidental findings from genetic testing? Clinical geneticist Conny van Ravenswaaij-Arts from the University Medical Center Groningen believes that national guidelines should be drawn up to cover this, and in consultation with all involved, which means patients too. ‘Doctors have a strong tendency to determine what is right for the patient, but we know little about what the patients themselves actually want.’

Conny van Ravenswaaij-Arts
Conny van Ravenswaaij-Arts

With traditional chromosome testing, chromosomes are studied under a microscope. However, only relatively large abnormalities can be traced using this technique and it is therefore increasingly being replaced by the array technique, a test to trace miniscule chromosome flaws − for example to diagnose children with delayed development. Van Ravenswaaij-Arts says, ‘The advantage of the array technique is that you are much more likely to be able to make a diagnosis. The disadvantage is that you also find lots of other things, the meaning of which we do not know – at least not yet. Or you discover that someone is missing the gene that would protect him or her from intestinal cancer. Such incidental findings will take on an even greater role once next generation sequencing is applied, which allows you to analyse all 20,000 genes in one single test.’


Van Ravenswaaij-Arts thinks it is necessary to decide how the medical world should deal with this, particularly in the case of children. ‘An adult is perfectly capable of deciding for himself what he does and doesn’t want to know, and is also able to consider the consequences. But what do you do if parents have said they don’t want information about any incidental findings when you know that their child has an increased likelihood of a treatable kind of intestinal cancer? Can you justify not telling them this?’

Big differences

Van Ravenswaaij-Arts is a member of an international taskforce that is giving thorough consideration to how to implement the array technique in prenatal diagnostics. ‘There is a big difference between the US and Europe in this field. In the US the thinking is that all pregnant women have the right to such a genome-wide test. In Europe prenatal diagnostics mainly focuses on detecting Down’s syndrome and that can be done perfectly well with microscopic research or the cheaper test known as the “quick test”.’

Listening better

Van Ravenswaaij-Arts wonders whether doctors really do know which questions future parents want answered. ‘Is the question, Does my child have Down’s syndrome? Or is the question actually, Is my child completely healthy? With an array test you can detect many more abnormalities than Down’s syndrome alone. Is it still the best approach then? In that respect doctors should listen better to their patients and it is high time for a study of pregnant Dutch women and their partners.’

Right decision

The diagnostics should focus on providing people with information that helps them make the right decision. Van Ravenswaaij-Arts says, ‘I think people can cope with much more than we tend to believe. A doctor should listen and ask questions on the basis of his or her findings. The doctor can then decide what the right approach is for that patient.’

Extensive public information programme

The first step in the right direction would be to provide the public with extensive information. ‘People need to know what genetic information is exactly, what you can do with it and what it means for family members. In many cases the genetic testing mainly relates to hereditary forms of dementia or cancer, for example. In that case a doctor does not have a single patient in front of him, but in actual fact a whole family that may not yet know anything about its hereditary predisposition.’

Van Ravenswaaij-Arts says, ‘We must also take into consideration that a significant number of parents have a low level of education or do not speak Dutch very well. Short and succinct films on the internet could be a great aid when advising patients prior to genetic testing. Permission from well-informed patients remains a requirement before genetic studies can take place − regardless of whether it is a chromosome test or the analysis of one or a few thousand genes.’

Curriculum vitae

Prof. Conny van Ravenswaaij-Arts (1961, Eindhoven) studied Medicine at Leiden University. She was awarded her PhD in Medical Sciences by Radboud University Nijmegen for her dissertation Heart rate variability: physiology and clinical applicability in very preterm infants. She continued her medical specialization in clinical genetics and clinical cytogenetics and has worked since 2006 at the UMCG as a clinical geneticist at the Department of Genetics. She was appointed Professor of Clinical Dysmorphology and the use of Genome Analysis in 2011.

Last modified:15 September 2017 3.10 p.m.
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