Nuclear transfer to prevent mitochondrial DNA disorders: revisiting the debate on reproductive cloning

Preclinical experiments are currently performed to examine the feasibility of several types of nuclear transfer to prevent mitochondrial DNA (mtDNA) disorders. Whereas the two most promising types of nuclear transfer to prevent mtDNA disorders, spindle transfer and pronuclear transfer, do not amount to reproductive cloning, one theoretical variant, blastomere transfer does. This seems the most challenging both technically and ethically. It is prohibited by many jurisdictions and also the scientific community seems to avoid it. Nevertheless, this paper examines the moral acceptability of blastomere transfer as a method to prevent mtDNA disorders. The reason for doing so is that most objections against reproductive cloning refer to reproductive adult cloning, while blastomere transfer would amount to reproductive embryo cloning. After clarifying this conceptual difference, this paper examines whether the main non-safety objections brought forward against reproductive cloning also apply in the context of blastomere transfer. The conclusion is that if this variant were to become safe and effective, dismissing it because it would involve reproductive cloning is unjustified. Nevertheless, as it may lead to more complex ethical appraisals than the other variants, researchers should initially focus on the development of the other types of nuclear transfer to prevent mtDNA disorders.

Lifestyle-related factors and access to medically assisted reproduction

Lifestyle is increasingly recognized as an outcome-determining factor in assisted reproduction, not only with regard to the cost-effectiveness but also in view of the balance of benefits and risks, including risks related to the welfare of the future child. This document briefly summarizes the evidence concerning the impact of three lifestyle-related factors (obesity, tobacco smoking and alcohol consumption) on both natural and assisted reproduction (IVF) and discusses the implications of this for the practice of medically assisted reproduction in the light of relevant ethical principles. The central question is whether and to what extent fertility treatment of obese, smoking or drinking patients should be made conditional on prior lifestyle changes.

The green grass on the other side: crossing borders to obtain infertility treatment

BACKGROUND

Cross-border reproductive care, also known as reproductive tourism, is a growing phenomenon. More and more treatments, or parts thereof, are taking place in countries other than the patient's home country.

RESULTS

The phenomenon is presented as a safety valve that takes the pressure of the restrictive legislation and simultaneously allows people to obtain the treatment they desire. These movements also hold a number of risks, both for the travelling patients and for the gamete donors and infertile couples in the country of destination. Finally, the possible role of patient organisations and medical professional societies is discussed.

Ooplasmic and nuclear transfer to prevent mitochondrial DNA disorders: conceptual and normative issues

BACKGROUND; Mitochondrial DNA (mtDNA) disorders are an important cause of human diseases. In view of the limitations of prenatal diagnosis and preimplantation genetic diagnoses, alternatives such as ooplasmic transfer (OT) and nuclear transfer (NT) have been proposed to prevent the transmission of mtDNA mutations. Both OT and NT are radical in the sense that they do not entail genetic selection, but genetic intervention to correct the genetic cause of the disease.

METHODS

After interviews with experts in the field, the relevant literature was searched and analyzed. Bioethical issues were divided into conceptual and normative points.

RESULTS

OT is the transfer of normal mitochondria to a carrier's oocyte containing mutant mtDNA. In case of NT, a donated oocyte is enucleated and replaced with the nuclear DNA from a woman carrying a mtDNA mutation. NT can be performed both before and after in vitro fertilization, respectively, with the nucleus of an unfertilized oocyte, with the pronuclei of the zygote, or with the nucleus of a blastomere of an embryo. Conceptual questions regard whether these techniques amount to germ-line modification and human cloning. Normative questions concern, among others, the significance of intervening in the mtDNA, the implications of having 'three genetic parents', the ethics of oocyte donation and the health and safety risks for children conceived as a result of one of these techniques.

CONCLUSIONS

Further interdisciplinary debate and research is needed to determine whether a clinical application of OT and NT can be morally justified, and if so, under which conditions.

PGD to reduce reproductive risk: the case of mitochondrial DNA disorders

This paper discusses the pros and cons of introducing PGD for mitochondrial DNA (mtDNA) disorders such as NARP (Neurogenic muscle weakness, Ataxia, Retinis Pigmentosa)/Leigh, MELAS (Mitochondrial myopathy, Encephalopathy, Lactic acidosis, and Stroke-like episodes), private mtDNA mutations and LHON (Leber Hereditary Optic Neuropathy). Although there is little experience with PGD for mtDNA disorders, it is reasonable to assume that in many cases, the best one can achieve is the selection of the 'least' affected embryos for transfer. So instead of 'promising' parents a healthy child, PGD in these cases can only aim at reducing reproductive risk. From an ethical point of view, this raises challenging questions about parental and medical responsibilities. The main argument in favour of PGD is that it offers couples at risk the opportunity of reducing their chances of having a severely affected child. Potential objections are manifold, but we conclude that none of them supplies convincing moral arguments to regard risk-reducing PGD as unacceptable. Nevertheless, introducing this new application of PGD in clinical practice will raise further complex issues of determining conditions for its responsible use.

ESHRE Task Force on Ethics and Law 13: the welfare of the child in medically assisted reproduction

The analysis of the welfare of the child in the context of medically assisted reproduction is divided in two parts: the first part addresses the risks associated with the would-be parent(s), the second part focuses on possible risks inherent in the technologies and treatments themselves. The risk factors connected with the intended parents may be medical and psychosocial. Two important considerations are raised here: the necessity to avoid discrimination and respect for the privacy of the patients. The second part concerns the ethical questions involved in the rapid dissemination of new technologies in assisted conception. Technology and research must always be subordinate to the welfare of the future offspring. The different steps involved in the responsible application of medical technologies to treat infertility are analysed.