Mitochondrial disorders in muscle.

The successful analysis of mutations in mitochondrial DNA has been a major step forward in our understanding of a number of baffling clinical syndromes, and the application of new technology to analyze and study mitochondrial DNA mutations has led to new insights into the pathogenesis of these disorders. Moreover, the field of mitochondrial DNA diseases is now expanding beyond the limited purview of relatively rare disorders to encompass clinical phenotypes that may be much more frequent in the population.