The fourth series of BBC Radio 4′s bioethics programme Inside the Ethics Committee began on August 6 2008, and discussed some of the ethical issues involved in the creation of ‘saviour siblings’ (first broadcast on BBC Radio 4, at 20.00, August 6 2008 and repeated on August 9 2008, at 22.15). Vivienne Parry and a panel of experts discuss the ethical issues around real-life medical cases, on this occasion the dilemma involves a young child, Catherine, and her medical treatment. Previous BioethicsBytes posts have noted the utility of this series (see the post Making tricky decisions – Inside the ethics committee), and this episode is no different.
Shortly after she was born Catherine was diagnosed with Diamond Blackfan Anaemia (DBA). DBA is a rare blood disorder caused by a genetic mutation. In general, its treatment is “gruelling” (00:02:27) and the prognosis is poor. As in several previous cases (notably, the Whitaker, Fletcher and Mariethoz families), Catherine’s parents were offered the option of using preimplantation genetic diagnosis (PGD) for tissue typing alone in order to create a ‘saviour sibling’ whose umbilical cord blood could be used to treat Catherine’s DBA.
Many of the ethical issues involved in this choice have been dealt with in past BioethicsBytes posts (see The Future of Our Families? and the extended commentary that accompanies that post), however this edition of Inside the Ethics Committee brings consideration of these issues up to date. Though the majority of the ethical issues raised are covered in our existing posts, some of the additional details noted here about DBA and the testing procedure introduce new complications into the ethical debate.
Creation of saviour siblings for children with DBA attracted attention in the early 2000s because it was an early example of the intention to use PGD for tissue typing alone. However, this debate may not have acknowledged how complicated this disease was, particularly for the purposes of creating saviour siblings. In previous posts, DBA has been presented as being caused by either an inherited or a spontaneous genetic defect. However, in practice this ‘either/or’ may not be clear cut distinction. While some of the inherited mutations that cause DBA have been characterised and can be identified in testing, it is suspected there are many other unknown mutations which also run in families. These, like spontaneous mutations, cannot be detected by testing kits available at present. Further, as the programme notes, family history (which can reveal the presence of an unknown mutation) may also be unreliable in the case of DBA. This is because the disease can appear in both a childhood or adult form. This means that even though a person may appear to be free from disease they may have an undiagnosed adult form.
In terms of the conception of a saviour sibling for a child with DBA this introduces the following complications: although – as in Catherine’s case – the child’s DBA may appear to be caused by a spontaneous mutation, it may actually be caused by an uncharacterised inherited mutation which has yet to manifest itself in adult members of the family. This means that in conceiving a second child – by natural means or through IVF – the sick child’s parents risk not only the unwitting conception of another child with DBA, but also an umbilical cord blood transplant from the new child to the older sibling would simply pass back the same mutation once again. In this situation, it might be concluded that the parents are doing their children a ‘double harm’, by having a second child afflicted with DBA and putting their existing child through a dangerous and painful transplant operation. While this complication may be specific to cases involving DBA, it is a possibility that may significantly change the dynamics of the ethical arguments presented in previous posts.
The complications concerning DBA noted above also draw attention to the reliability of testing procedures and the confidence that can be placed in their results. This is another area in which this edition of Inside the Ethics Committee adds to our previous posts. While some uncertainties are obviously inherent within all testing procedures, previous posts have not made their consequences explicit, nor have any of their sources been identified. Here, Professor Peter Braude, a leading fertility doctor, identifies a number of complications in using cells biopsied from an embryo for tissue typing: “you can’t make the diagnosis, there’s something else wrong or the test didn’t work” (00:08:38). Further, in discussing the routine use of aneuploidy testing during IVF in the US, he notes that “when you take a cell from an embryo the premise of the whole test is that all the cells of the embryo are the same. And that is not necessarily the case” (00:22:16). These factors impact upon both, the likelihood of obtaining a definitively tissue matched embryo that is unaffected by any genetic or chromosomal abnormality in any one IVF cycle, and the numbers of embryos that are discarded during what may be several IVF cycles. The implications of these uncertainties are, as the programme notes, that the chances of a couple undertaking IVF in order to create a saviour sibling “going home with the baby is probably not much better than 1 in 10″ (00:08:53), and that a number of embryos that could have created healthy, tissue matched siblings may be wrongly discarded in the testing process. Again, both these considerations may alter the dynamics of the ethical arguments presented in previous posts.
Above I highlighted those aspects of the case discussed in the August 6 2008 edition of Inside the Ethics Committee which extend previous BioethicsBytes posts on ‘saviour siblings’. Finally, I turn to the crux of the problem debated by the Radio 4 panel, and the comparisons between this real-life case and the fictional scenario developed by Jodi Picoult in her book My Sister’s Keeper (Picoult, 2004). As with all the cases presented in this series, at the time of broadcast, the decision regarding the creation of a saviour sibling for Catherine had already been made. MacKenzie, Catherine’s sister, was born following the revision of Human Fertilisation and Embryology Authority (HFEA) guidelines on this issue, and her umbilical cord blood was collected for transplant into Catherine. However, in this case, clinicians were unable to collect enough stem cells for the procedure. This lead to the situation where the only option for treating Catherine was a bone marrow transplant from the infant MacKenzie. At the risk of spoiling the conclusion of the programme for future listeners, this operation took place in 2006, and was a decision that the Radio 4 panel generally approved of. It is notable that many of the ethical, legal and social issues implicit in this choice are pre-empted by Picoult’s (2004) fiction: Picoult’s saviour sibling, Anna, is also required to donate bone marrow to her sister, Kate, at a very young age – a situation the narrative explores from the viewpoints of each member of the family.
However, unlike this edition of Inside the Ethics Committee, Picoult’s story takes the issue of tissue donation by saviour siblings to the next stage: the donation of a solid organ. Whilst this is touched on in the radio broadcast the issues around this are better explored in Picoult’s work. However, what might be called the ‘slippery slope’ of tissue donation from saviour to sick siblings, does lead to the panel’s eventual conclusion around how these ethical issues and choices might be resolved in practice. Braude, for example, states: “all these ethical issues are coming up at this stage but the majority of them are actually predictable earlier. And this is where the importance is of actual good counselling. Right at the very start of this, what this might mean if various scenarios need to be played out” (00:31:24).
Dr. Simon Meller adds: “the counselling and permission needs to be obtained right at the beginning of the process before the tissue typing is carried out” (00:33:57). Although the panel all seem to agree that this may be the best (and perhaps only) way to deal with the ethical complexities that come up as saviour sibling cases play themselves out in real life, they also suggest that, in a situation like that of Catherine and her family, “it’s very understandable that the parents should consider the short term benefits…first” (00:35:04) – a sentiment it seems difficult to reconcile fully with counselling and consent as guarantors of the best interests of two children who may have conflicting needs that change over time.
All timecodes given in this post refer to the ‘listen again’ version of this broadcast available on BBC iPlayer. In addition to the recording, there is also a transcript of the discussion. Alternatively, audio recordings can be obtained from the BUFVC.