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Why treat PGD for late onset disorders differently?

4 May 2005
By Mohammed Taranissi
Assisted Reproduction and Gynaecology Centre) and James Lawford Davies (Bevan Brittan)
Appeared in BioNews 306
Like so many areas of new reproductive and genetic technology, PGD for susceptibility and late onset disorders needs careful attention. It raises some unique questions, and the recent decision of the Human Fertilisation and Embryology Authority (HFEA) to license PGD for bowel cancer has attracted much criticism from those who believe that this is another step towards eugenics and the commodification of human life. It may not be possible to reach a consensus on such complex medical, ethical and legal problems. However, they still warrant debate and discussion so as to better inform the application of PGD in this area, which is currently left to the discretion of the HFEA.

PGD is subject to a two-track licensing system in the UK. The fast track is for clinics with a proven expertise in performing embryo biopsies that are applying for a licence to screen for a condition which is already being carried out successfully in another clinic. The HFEA will approve such applications without putting them through the full licence committee process, providing the same technique and methods are to be used. The slow track is for applications for new conditions, HLA (human leucocyte antigen) typing, and PGD for late onset conditions or susceptibility genes. These applications will be considered by a licence committee on a case-by-case basis which experience suggests could take up to six months.

The rationale behind the decision to put PGD for susceptibility and late onset conditions on the slow track is not clear. In its press release on the subject, the HFEA said only that these were 'less common specialised applications'. In fact, the technique applied in PGD is the same regardless of the point at which a disease may develop in the resulting child: it is no more or less specialised, and the frequency of its application is therefore largely irrelevant.

Likewise, where applications for susceptibility or late onset disorders are considered by the HFEA, there is also a degree of uncertainty as to how they are assessed. Again, the clearest indication we have is from their communications department. When commenting on the HFEA's decision to grant a licence for PGD for bowel cancer, a spokesperson referred to two factors that were taken into account in approving the application: the cancer could strike as early as ten, and the gene involved made the disease '100 per cent certain'. In fact, certainty cannot be guaranteed in such cases but, that aside, the comments are unhelpful to those of us who would like a proper understanding of the criteria that might be taken into account by a licence committee assessing such an application.

As the joint HFEA and Human Genetics Commission (HGC) consultation highlighted, 'late' onset disorders are difficult to define and debate: for example and in contrast with the bowel cancer application, what if the disease under scrutiny would not develop until the affected adult was 20, or 40? What if, as with certain breast cancer mutations, the likelihood of development is around 50 per cent? What other factors, if any, will be weighed in the balance by the licence committee when it meets behind closed doors? In the absence of any clear policy or assessment criteria in this area we can only guess the answers to these questions. This in turn creates an uncomfortable situation for doctors and patients who cannot assess the likely outcome of any application they might choose to make.

This is not to say that a policy or list of assessment criteria is an ideal solution but, in the context of the existing HFEA licensing process, some understanding of how decisions are made is better than none. However, looking to the future, the government's review of this area creates at least the possibility of a new approach.

As mentioned, PGD for susceptibility and late onset disorders raises some novel questions. Amongst other things, it impacts in a distinct way upon the consent obtained from patients, the disclosure of information to them before and after treatment, the need to follow up children born through its application, and a range of factors to be taken into account where one or both parents may be affected by the disorder in question. Such matters deserve open and well-informed debate and discussion. To that end, tonight's Progress Educational Trust debate on the ethical implications of PGD for late onset disorders is very welcome. Events such as this provide an opportunity to hear arguments for and against the application of PGD in this context. This in turn better informs those who are best placed to make the decisions as to whether or not to proceed with treatment in a given case: patients and their doctors.


4 April 2007 - by Dr Jess Buxton 
According to the Sunday Times newspaper, a UK clinic is requesting permission to test embryos in order to select those free from early onset Alzheimer's disease. Charl and Danielle de Beer are planning undergo IVF treatment in conjunction with preimplantation genetic diagnosis (PGD) at the Bridge...
11 May 2006 - by Dr Jess Buxton 
The UK's fertility treatment regulator has given the go-ahead for couples to test embryos to avoid passing on hereditary cancer. At its open meeting held on 10 May in Belfast, the Human Fertilisation and Embryology Authority (HFEA) accepted a recommendation from its ethics and law committee...
10 November 2005 - by BioNews 
The UK's Human Fertilisation and Embryology Authority (HFEA) has launched a public debate on testing embryos for 'lower penetrance', late onset genetic disorders. A discussion paper, entitled 'Choices and Boundaries', focuses both on genetic tests currently available, such as that for hereditary breast cancer, and possible future developments, such as...
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