the safety and effectiveness of these techniques, and does not consider the ethical and legal issues that are raised by such techniques.
The methodology of the review is set out at annex B and the evidence reviewed is listed at annex C. The panel looked in particular at the current use of PGD and the recent advances in MST and PNT research that may be applied to diseases caused by mtDNA mutations. The review focuses on mtDNA mutations and only peripherally on mitochondrial disease due to mutations in nuclear DNA, for which MST and PNT techniques are not relevant. However, the panel recognises that these are also serious diseases that deserve attention. The panel also recognises that oocyte donation can be used to avoid mtDNA associated mitochondrial disease and to eliminate it from descendants. However, this option is not one favoured by patients who desire to have their own genetic children and is beyond the scope of this scientific review.
This report is structured as follows: section 2 provides an overview of mitochondrial biology and disease; section 3 considers and makes recommendations on the use of PGD to avoid mitochondrial disease; sections 4 and 5 consider the effectiveness and safety of MST and PNT, and suggest further research. The review makes a number of conclusions and recommendations throughout, which have been highlighted in bold text. These are summarised in section 6 of the report. In addressing its terms of reference, the panel has tried to set out the issues in as clear manner as possible. However, as the biology of mitochondria is complex, the language used is necessarily technical in parts. A glossary is supplied at annex D.
Background information on mitochondrial biology and disease
2.1 Mitochondria are the energy-producing organelles in the cytoplasm of every mammalian cell. Mitochondria produce much of the energy in a cell, in the form of adenosine triphosphate (ATP) via oxidative phosphorylation reactions involving the electron transfer chain (ETC). Energy is required for cells to synthesise proteins and other molecules, to
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