Pre-Implantation Genetic Diagnosis (PGD)

Introduction

PGD - Screening
Pre-implantation genetic diagnosis (PGD) is a reproductive technology used in the context of IVF to ‘screen’ embryos prior to implantation. It enables genes and chromosomes to be checked for different genetic conditions. People at risk of passing on such conditions may use PGD to select an embryo that does not have a particular condition, and therefore to have a healthy child. PGD may also be used for the purposes of sex selection, in order to avoid a sex linked disorder, and together with human leukocyte antigen typing (HLA typing) to create a ‘saviour sibling’. That is, a sibling that may be used as a donor to another child who is already alive and suffering from a particular disorder.

Click on the button below to see examples of the vast number of conditions that PGD may be used to detect.

PGD List of Conditions

State and Territory Laws:
Screening for Disease and Disorder

Relevant legislation exists in Victoria, South Australia and Western Australia.
Victoria

Victoria

In Victoria, PGD is permitted in order to prevent a genetic abnormality or disease in the embryo. 1

The Assisted Reproductive Treatment Act however does not define ‘genetic abnormality or genetic disease’ because ‘Parliament intended the words to receive a broad, purposive interpretation’.

The Victorian Assisted Reproductive Authority (VARTA) does not oversee PGD generally, unless PGD is intended for sex-selection, or is being carried out for a reason other than a potential risk of transmitting a genetic condition if the participants were to conceive naturally. In these instances, an application must to be made to the Victorian Patient Review Panel for approval. 2 The Patient Review Panel must adhere to the Act’s prioritising of the welfare of any child who may be born following the process. The Patient Review Panel, and the Victorian Civil and Administrative Tribunal (on appeal), have held that sex selection for family balancing focuses on the needs of the parents and the existing children, rather than focusing on the welfare of the future child. 3

South Australia

South Australia

In South Australia the Assisted Reproductive Treatment Act 1988 (SA) permits the use of PGD ‘if there appears to be a risk that a serious genetic defect, serious disease or serious illness would be transmitted to a child conceived naturally’. 4 The NHMRC Ethical Guidelines remain relevant for further guidance.
Western Australia

Western Australia

In Western Australia diagnostic procedures may be carried out on embryos, if ‘there is a significant risk of a serious genetic abnormality or disease being present in the embryo.’ 5 The diagnostic procedure must be unlikely to leave the embryo unfit to be implanted in the body of woman. 6 

Guidance from the Western Australian Reproductive Technology Council states that  ‘in assessing whether a genetic abnormality or disease is serious it is appropriate to look at environmental and personal factors as well as the impairment to body functions and structures that may arise from the condition. The assessment should consider the limits that these factors impose on the extent to which a person can engage in activities or participate in life situations.’ 7  In relation to what constitutes a ‘serious risk’, the Reproductive Technology Council requires that ‘the risk of the disease or disability occurring’ in the embryo must be higher than in the general population, however recognises that the views of the person seeking treatment may also be relevant when assessing significance and one cannot rely on statistics alone. 8

PGD and Sex Selection

Baby - PGD
PGD may be used to select the sex of a child for medical reasons to avoid a sex-linked disorder (for example a disorder linked to the X chromosome such as heomophilia, a bleeding disorder). The laws governing PGD to screen for such disorders are described above.

PGD may however, also be used for sex-selection for non-medical reasons. That is, when a family wishes to have a child of a certain sex (male or female) due to preference or ‘family balancing'(that is they already have children of one sex and wish for a child of the other sex).

A 2013 poll of Australians showed that they overwhelmingly opposed sex-selection for non-medical social reasons. While 91% of people supported the use of IVF to help infertile couples, only 20% supported gender selection using PGD within IVF or for family balancing. When it came to the use of IVF only for gender selection, only 17% were in favour. 9

The strong opposition usually reflects concern about sex discrimination, population gender imbalance (for example, too many males in a particular population) and the best interests of the child.

The use of PGD for non-medical reasons in Australia is prohibited.

PGD and HLA Typing

Baby - PGD for HLA Typing
PGD for HLA typing involves creating a child with tissue type that matches that of an existing sibling who requires tissue or organ donation due to illness. It is only relevant where the need for such tissue/organs is non-urgent (as the child would have to wait the time taken for the course of a pregnancy and beyond). It is also only relevant where parents are of a reproductive age. It may be considered when no other donor is available, and the only possibility of finding a donor is through a matched sibling.

The use of PGD for HLA typing has been controversial, as it has been seen by some as unacceptable to create a child for the purposes of using it to save another. There are also issues surrounding the pressure on the child born to donate tissues or organs, and freedom of consent.

Others note that the child would be loved in its own right, and would not solely be considered a source of tissue or organ.

In Australia, the NHMRC Guidelines require clinicians to ‘seek advice from an independent body before undertaking PGT to select an embryo with compatible tissue for subsequent stem cell therapy’. The independent body should be satisfied that there is no evidence to suggest that the person who would be born would not be a welcomed, respected member of the family unit; the use of PGT will not significantly affect the welfare and interests of the person who would be born; the medical condition of the intended parent, sibling or other relative to be treated is serious and stem cell treatment is the medically
recommended management of the condition. 10

All states and territories follow such guidelines.

In Victoria, any such screening would also have to be approved by the Patient Review Panel.

National Guidelines and Oversight

The NHMRC Ethical Guidelines are again relevant.

They provide guidance to all clinics across Australia.

Some states have specific legislation too.

See below.
In Australia, the NHMRC Ethical Guidelines provide clinics with guidance on the use of PGD and HLA typing. The guidelines recognise that PGD may only be used to select against genetic conditions, diseases or abnormalities that would severely limit the quality of life of the person who would be born; select an embryo with compatible tissue for subsequent stem cell therapy intended for a parent, sibling or other relative; increase the likelihood of a live birth. 11 They state (among other things):

It is not possible to list the genetic conditions, diseases or abnormalities for which the use of PGT is ethically acceptable, as context is important and the assessment may change over time. Clinicians should consider the following criteria when assessing the ethical acceptability of the use of PGT:

  • current evidence and expert opinion on the impact of the condition, disease or abnormality on the quality of life of the person who would be born, including the anticipated symptoms, age-of-onset and the degree/spectrum or severity of the condition, disease or abnormality
  • the concerns of the intended parent(s) about their ability to care for a person born with the condition, disease or abnormality
  • the availability and accessibility of therapies or interventions to reduce the severity, delay onset or minimise the impact of the condition, disease or abnormality
  • the limitations of the technology, including the likelihood of false positive and false negative results
  • the experiences of individuals and families living with the condition, disease or abnormality
  • the potential for stigma to influence the perceived impact of the condition, disease or abnormality on the quality of life of the person who would be born
  • the extent of social support available to the intended parent(s) and to the person who would be born. 12

People seeking access to PGD should also be provided access to a geneticist and a genetic counsellor, and be given relevant information to enable informed decisions about treatment.

Notes:

  1. Assisted Reproductive Treatment Act 2008 (Vic) s 10(2)(a)(iii).
  2. Assisted Reproductive Treatment Act 2008 (Vic) s 28(2)(b).
  3. See JS and LS v Patient Review Panel [2011] VCAT 856 [54].
  4. The Assisted Reproductive Treatment Act 1988 (SA) s 9(1)(c)(iii).
  5. Human Reproductive Technology Act 1991 (WA) s 14(2b)(ii).
  6. Human Reproductive Technology Act 1991 (WA) s 14(2b)(i).
  7. Reproductive Technology Council, Policy on Approval of Diagnostic procedures involving embryos (2013) 5 [8].
  8. Reproductive Technology Council, Policy on Approval of Diagnostic procedures involving embryos (2013), 5[5]-5[7].
  9. Kovacs Gab , McCrann Julian, Levine Michele, and Morgan Gary, ‘The Australian Community Does Not Support Gender Selection by IVF for Social Reasons'(2013) International Journal of Reproductive Medicine
    Volume 2013, Article ID 242174, 3 pages http://dx.doi.org/10.1155/2013/242174
  10. National Health and Medical Research Council, Ethical Guidelines on the use of Assisted Reproductive Technology in Clinical Practice and Research (2017), [8.17.2].
  11. National Health and Medical Research Council, Ethical Guidelines on the use of Assisted Reproductive Technology in Clinical Practice and Research (2017) [8.15.1]
  12. National Health and Medical Research Council, Ethical Guidelines on the use of Assisted Reproductive Technology in Clinical Practice and Research (2017) [8.16.1].