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Ethical concerns over consumer genetic testing and autism

2 July 2010   |   By Dr Caroline Wright   |   Research article

The increasing availability of genetic tests available direct-to-consumer (DTC) has led to extensive international debate about the regulation of such services (see previous news). In particular, genomic profiles that offer individual risk prediction for a plethora of different common diseases have raised a number of ethical questions relating to the potential harms of giving this kind of probabilistic, and potentially misleading, information to individuals (see previous news) without formal genetic counselling or professional medical advice.

These issues are further elaborated in a new paper in the Journal of Medical Ethics, specifically in relation to testing for genetic susceptibility to autism [Jordan BR & Tsai DFC, JME (2010) doi: 10.1136/jme.2009.031385]. Autism is an increasingly prevalent neurodevelopment disorder which manifests in childhood and is broadly characterised by impaired social interaction and repetitive behaviour. Although twin studies suggest that the disorder is highly heritable, genome-wide association studies for both SNPs (see previous news) and CNVs (see previous news) have thus far failed to explain much of the genetic basis of this multifactorial disease; diagnosis still involves numerous psychological tests combined with professional judgement, and risk prediction remains impossible. Nonetheless, a genetic susceptibility test is frequently conjectured in the media and is actively being developed commercially (though is not currently offered by any of the major DTC genomics companies).

The authors question whether “a responsible test for autism could ever be commercially viable”, and suggest that this kind of genetic susceptibility test for multigenic diseases can only be useful if:

(1)   the gene-disease association is robust (i.e. proven scientific validity);
(2)   the relative risk conferred has a ‘significant’ clinical impact; and 
(3)   there is an improved outcome as a result of testing (i.e. proven clinical utility).
 
To date, none of these three criteria are adequately fulfilled for autism – or for many other common complex diseases. However, the authors argue that a putative autism genetic test is not like equivalent obesity or diabetes tests, because “a false positive result can be particularly damaging for early-age behavioural syndromes that are strongly influenced by the tone of parent-child interactions”.
 
Comment: This thought-provoking article raises a number of interesting issues. Rather than arguing for genetic exceptionalism, whereby genetic information is given ‘special’ treatment (which is both practically and philosophically problematic), the authors are advocating a kind of ‘behavioural exceptionalism’, whereby DTC tests for specific psychological disorders should not be allowed. Laudable as this sentiment may appear, as with any kind of exceptionalism, it is difficult to see where to draw the line. Moreover, in practice, it will be increasingly difficult to achieve as we move towards an era in which genome profiling, or even whole genome sequencing, becomes more commonplace, and the internet abounds with genomic analysis services and open access bioinformatics software.
 
There are also numerous issues relating to genetic testing of children, who are unable to give informed consent, and professional guidance generally recommends against testing except where there are immediate clinical benefits (see previous news). However, in the DTC setting, this could be difficult to achieve, and is potentially unnecessary for weakly predictive susceptibility tests. Before deciding what level of regulation is appropriate for these kinds of tests, evidence is needed that that the putative harms caused by testing really exist, and that they outweigh the potential benefits of allowing a free market approach.
 
Finally, the list of three requirements for a genetic susceptibility test to be useful are certainly right, and should form the cornerstone of evidence-based medicine upon which publicly-funded national health services are based. But they are probably too stringent for a test to be available privately. Aside from regulating the analytical validity, through laboratory oversight and quality assurance, the best way to address the thorny issue of interpretation in consumer testing may be through transparency of information, to ensure consumers are not mislead by probabilistic test results. 
Keywords: Direct to consumer tests, Disease Susceptibility (Genetic), Regulatory Framework

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