Abstract
The maternally inherited mitochondrial DNA (mtDNA) is a circular 16,569bp double stranded DNA that encodes 37 genes, 24 of which (2 rRNAs and 22 tRNAs) are necessary for transcription and translation of 13 polypeptides that are all subunits of respiratory chain. Pathogenic mutations in mtDNA cause respiratory chain dysfunction, and are the underlying defect in an ever-increasing number of mtDNA-related encephalomyopathies with distinct phenotypes. In this chapter, we present an overview of mtDNA mutations and describe the molecular techniques currently employed in our laboratory to detect two types of mtDNA mutations: single-large-scale rearrangements and point mutations.