It is currently not possible to predict the outcome of children born to mothers who are carrying by delerious mtDNA mutations such as those causing MELAS and MERRF, due to the variable amounts of abnormal mtDNA that are passed to each offspring.
This can make reproductive decisions very difficult for families. Gigarel et al in Am J Hum Genet. 2011 Apr 8;88(4):494-8. attempted to correlate mtDNA mutatant load (m.3243A>G, m.8344A>G, or m.9185T>G) between first polar bodies and their counterparts, either oocytes, blastomeres, or embryos. Unfortuantely, significant differences were observed between polar body and counterpart mtDNA mutant content. The group therefore concluded that differences in mutant content between polar bodies and their counterparts make this method of preconception diagnosis unreliable for the prediction of mtDNA disease recurrence.
Hilary Vernon MD PhD