Tuesday, 14 October 2014

Prenatal genetic testing and autism: a delicate subject

I realise that the paper by Lei-Shih Chen and colleagues [1] covers a most sensitive topic when it comes to the autism spectrum, exploring: "the attitudes toward PGT [prenatal genetic testingand termination decisions of 42 parents of children with ASD [autism spectrum disorder]". Indeed, this is not the first time that this research group has looked at this area of autism research [2] and it seems like they will be talking about it further too (see here).

I chose to discuss the most recent paper on this blog because (a) the Chen paper is peer-reviewed science, (b) the likelihood of PGT being 'applied to autism' at some point in the future is growing (if not here in some parts of the world?), and (c) similar to the screening tests available for conditions like Down's syndrome (see here), there are going to be conversations to be had about the decisions and choices potentially offered to parents on the basis of any screening results. Charities here in the UK such as Antenatal Results and Choices (ARC) are probably going to figure in those conversations which, in some quarters, have already begun to happen (see here). I write this blog from a cold, scientific perspective so please don't get offended by some of the discussions.

The Chen paper describes the results of a qualitative study where parents of children with ASD were given "a hypothetical scenario" regarding PGT and asked their hypothetical response to using PGT and their hypothetical response to a positive test response. "Of the 31 parents who were either willing or unsure about undergoing the PGT, approximately three-fourths would continue their hypothetical affected pregnancies".

A few things struck me about the Chen paper. First is a line introducing the abstract which reads: "In the United States, prenatal genetic testing (PGT) for Autism Spectrum Disorders (ASD) is currently available via clinical genetic services". I was quite taken aback by this sentence. As far as I was aware science was still feeling around as to the underlying genetics of autism (that is, if you consider autism to be a unitary concept rather than a more plural condition and to be solely driven by structural genetics over and above environmental factors or epigenetic changes). If someone is suggesting otherwise, please do point me towards the peer-reviewed science for that prenatal genetic test outside of something like just screening for Fragile X syndrome [3] or the preliminary results reported by Wapner and colleagues [4] mentioned with autism in mind...

The next thing that caught my eye was the high number of parents who, if faced with the hypothetical PGT situation, said they would continue with their pregnancy. I'm not so surprised at this, given that researchers were asking parents who already had a child with autism and so perhaps knew a little bit about both the good and not-so-good times which go with raising a child with a developmental disability. I also emphasise the word 'child' there before their condition/label. If the questions were put to parents with no personal experience of autism, one wonders whether similar outcomes would have been reported. Likewise if parents were for example, offered differing scenarios under such experimental conditions with other conditions outside of autism, such as Down's syndrome, the question remains about what results might have shown also bearing in mind the literature in this area [5].

Finally, and I again tread very carefully with this, was the observation that: "Parents who reported they would terminate the affected pregnancy in this hypothetical situation were primarily Asians". I go to great lengths on this blog not to over-generalise autism research such that not every finding has to apply to every single person with autism. In this instance I'd also point out that the sample size for the Chen results was very small and outside of cultural differences and representations [6], one similarly cannot assume that every person/parent of Asian origin is going to report like this. Neither however should judgement be passed on those parents who did choose this hypothetical option and the road(s) which might have led them to this hypothetical decision. This might however suggest that as per other examples, autism is looked at in very different ways according to factors such geography and culture.

As I mentioned at the top of this post, prenatal testing (genetic or otherwise) is always going to be a sensitive subject when applied to autism and will inevitably stir up considerable emotions for many people, not least those who are themselves on the autism spectrum. I'm going to leave you with some more discussion about this area from Prof. Andrew Whitehouse - he of the 'Is autism one or multiple disorders?' paper - and a very sensible post he wrote (see here) which covers most of the important issues well.

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[1] Chen LS. et al. Autism Spectrum Disorders: A Qualitative Study of Attitudes toward Prenatal Genetic Testing and Termination Decisions of Affected Pregnancies. Clin Genet. 2014 Sep 24.

[2] Chen LS. et al. Autism genetic testing: a qualitative study of awareness, attitudes, and experiences among parents of children with autism spectrum disorders. Genet Med. 2013 Apr;15(4):274-81.

[3] Gutiérrez JF. et al. Prenatal screening for fragile x: carriers, controversies, and counseling. Rev Obstet Gynecol. 2013;6(1):e1-7.

[4] Wapner RJ. et al. Chromosomal Microarray versus Karyotyping for Prenatal Diagnosis. NEJM. 2012; 367: 2175-2184.

[5] Scott CJ. et al. Prenatal diagnosis and termination of pregnancy: perspectives of South African parents of children with Down syndrome. J Community Genet. 2013 Jan;4(1):87-97.

[6] Bie B. & Tang L. Representation of Autism in Leading Newspapers in China: A Content Analysis. Health Commun. 2014 Jul 29:1-10.

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ResearchBlogging.org Chen LS, Xu L, Dhar SU, Li M, Talwar D, & Jung E (2014). Autism Spectrum Disorders: A Qualitative Study of Attitudes toward Prenatal Genetic Testing and Termination Decisions of Affected Pregnancies. Clinical genetics PMID: 25251361