[Application of long PCR method to detection of mitochondrial DNA deletions in mitochondrial encephalomyopathies]

In 1994, Barnes found the new method "long PCR method" where over 10 kb DNA was easily amplified, compared with conventional PCR method in which only a few kb DNA was amplified. He devised the new enzyme in this system which included Taq DNA polymerase plus a little amount of 3'-->5' exonuclease activity (proofreading activity). We tried to apply this method to detect mitochondrial DNA deletions in mitochondrial encephalomyopathies. We detected mtDNA deletions easily, however, we could not quantify mtDNA deletions. This method can be performed within one day, compared with about 1 week required to perform Southern blotting and/or several sets of conventional PCR. Although Southern blotting is needed for quantifying mtDNA deletions, this method will become a useful screening method for detecting mtDNA deletions.