Amplification of DNA sequences in polar bodies from human oocytes for diagnosis of mitochondrial disease.

When a preovulatory oocyte reinitiates meiosis, it sheds a cytoplasmic fragment containing mitochondria and a redundant set of chromosomes. We have detected DNA sequences from both the mitochondrial and nuclear genomes in polar bodies from unfertilised human oocytes, demonstrating the feasibility of diagnosing mitochondrial diseases before conception.