Mitochondrial replacement techniques: The perspectives of mitochondrial disease specialists in Germany

'Mitochondrial disease' is an umbrella category for neurogenetic and metabolic diseases which are associated with mitochondrial dysfunction caused by genetic variations in either mitochondrial DNA (mtDNA) or nuclear DNA (nDNA). This article draws on interviews with four mitochondrial disease specialists in Germany in order to explore their perspectives on mitochondrial replacement techniques (MRTs), emerging 'IVF-based technologies' which could potentially prevent the transmission of mitochondrial DNA disease. MRTs aim to exchange (or replace) the cytoplasm of an intended parent's egg cell, which contains disease-causing mtDNA, with the cytoplasm from an egg cell of another individual (aka the mitochondrial donor). MRTs are legal and regulated by assisted reproduction legislation in the UK (since 2015) and Australia (since 2022) for the explicit purpose of reducing the risk of transmitting an mtDNA variant associated with a high risk of severe mitochondrial disease. MRTs are not available in Germany. In other countries, MRTs are offered by fertility clinics for a variety of indications, ranging from the prevention of mitochondrial disease to broader experiences of fertility difficulties. Mitochondrial disease specialists in Germany emphasized the predictability of mitochondrial unpredictability and a mitochondrial disease severity spectrum. Closely engaging with the use of two concepts by the specialists I interviewed-'predictability/unpredictability' and 'severity'-which also appeared in formal and public representations and discussions in the UK, I show how the invocation of these notions may paradoxically both enable and curtail support for the clinical implementation of MRTs.