Genetic and epigenetic modifications associated with human ooplasm donation and mitochondrial heteroplasmy - considerations for interpreting studies of heritability and reproductive outcome.
The mitochondrial heteroplasmy present in offspring from IVF and human ooplasm donation is troublesome and merits further exploration in a debate that is already complex and controversial. Improving the understanding of mitochondrial genomics in this context is important because mitochondriopathies can impact crucial cellular processes in renal, cardiovascular, central nervous, and endocrine systems. Relevant epigenetic consequences of mitochondrial heteroplasmy include associated abnormalities in mitochondrial translation products. Furthermore, as transmission and inheritance patterns of mtDNA are species-specific, it remains to be proven if findings derived from animal studies are applicable to human offspring. As an alternative to gamete research and proteomics based on animal experimentation, continued molecular characterization of the de novo human mitochondriopathies is posed to offer further insights regarding mitochondrial heteroplasmy. In this context, because knowledge of human mitochondrial genetics remains limited and the risks associated with ooplasm donation cannot be quantified, we do not favor its use for our patients at present. However, the small number of infants already conceived from this experimental approach warrant careful longitudinal evaluation. In particular, observational study of the few children born after ooplasm donation could provide opportunities to assess human mtDNA transmission and inheritance. Such findings could help identify features distinguishing natural mtDNA heteroplasmy from heteroplasmy observed after ooplasm donation. Future investigations should also quantify the degree any such heteroplasmy can exist innocuously. Disclosure of mtDNA mutations potentially affecting children conceived from IVF and ooplasm donation must be included during patient education at centers contemplating such treatment.
Sills
E Scott
ES
Cornell Institute for Reproductive Medicine and Infertility, Weill Medical College of Cornell University, New York-Presbyterian Hospital, New York, USA. dr.sills@ivf.com
Takeuchi
Takumi
T
Tucker
Michael J
MJ
Palermo
Gianpiero D
GD
D000818:Animals; D003593:Cytoplasm / Q000637:transplantation*; D004272:DNA, Mitochondrial / Q000235:genetics* / Q000378:metabolism*; D044127:Epigenesis, Genetic; D005260:Female; D005307:Fertilization in Vitro; D005544:Forecasting; D015870:Gene Expression; D023281:Genomics; D006801:Humans; D018587:Oocyte Donation; D009865:Oocytes / Q000502:physiology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D013045:Species Specificity
D004272:DNA, Mitochondrial