This paper aims to address the ethical issues regarding prenatal diagnosis and preimplantation genetic diagnosis (PGD) of mitochondrial disorders. Owing to the absence of effective treatment, the prevention of the transmission of mitochondrial disorders is considered to be of key importance. The characteristics of mtDNA, such as heteroplasmy and the genetic bottleneck, make it difficult to estimate recurrence risks correctly and to provide an accurate prognosis for many mtDNA mutations. A limited number of mtDNA mutations allow reliable predictions, though results in the 'grey zone' are problematic. Both prenatal diagnosis and PGD for mtDNA disorders are complicated by the interpretation of the test results. As a consequence, these applications confront both clinical practice and society at large with several ethical questions and issues for further debate, among which the acceptability of suboptimal genetic testing, the value and research use of embryos, the evaluation of late abortion, the ethics of PGD for disorders with an incomplete penetrance and variable expression, the possible transfer of embryos with residual health risks, the acceptability of risks and drawbacks of genetic reproductive technology in general, and the scope and limits of reproductive autonomy and professional responsibility.

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.

Although a scientific and ethical debate about the possible reproductive options for carriers of mitochondrial DNA (mtDNA) mutations is developing, not much information regarding the views and experiences of professionals exists. This paper explores the attitudes and experiences of professionals involved on a daily basis with their patients' reproductive decision-making in the context of mtDNA disease. Qualitative international multicenter design using in-depth semi-structured interviews with 20 professionals has been utilized. We identified four main themes emerging from the interviews. Firstly, we illustrate the discussion among professionals as to what extent mitochondrial genetics differs from other areas in genetics, both technically and ethically. Secondly, we show the discomfort and doubts of professionals when an mtDNA mutation is involved, because of the uncertainty remaining after testing. Thirdly, we discuss how professionals struggle with the tension between, on the one hand, the ideal of reproductive autonomy and, on the other hand, the reality of their professional responsibility and complex clinical decision-making. Fourthly, we delineate the strategies used by professionals in order to make attempts to control uncertainty. This paper illustrates the impact on professionals of reproductive decision-making in the context of mtDNA disease. It shows their feelings of discomfort when interpreting and explaining uncertain or ambiguous data and may be perceived as an example of how professionals deal with the inherent limitations in genetic knowledge representing the state of the art. Insight into the experiences of professionals may contribute to a further improvement of reproductive genetic counseling in the context of mtDNA disorders.

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