MITOCHONDRIAL-DNA MUTATIONS AND PATHOGENESIS

Approximately three years ago, this journal published a review on the clinical and molecular analysis of mitochondrial encephalomyopathies, with emphasis on defects in mitochondrial DNA (mtDNA). At that time, a pproximately 30 point mutations associated with a variety of maternall y-inherited (or rarely, sporadic) disorders had been described. Since that time, almost twenty new pathogenic mtDNA point mutations have bee n described, and the pace of discovery of such mutations shows no sign s of abating. This accumulating body of data has begun to reveal some patterns that may be relevant to pathogenesis.