Camptocormia as a Novel Phenotype in a Heterozygous POLG2 Mutation.

Mitochondrial dysfunction is known to play a key role in the pathophysiological pathway of neurodegenerative disorders. Nuclear-encoded proteins are involved in mtDNA replication, including DNA polymerase gamma, which is the only known replicative mtDNA polymerase, encoded by nuclear genes Polymerase gamma 1 (POLG) and Polymerase gamma 2 (POLG2). mutations are well-known as a frequent cause of mitochondrial myopathies of nuclear origin. However, only rare descriptions of mutations leading to mitochondriopathies exist. Here we describe a 68-year-old woman presenting with a 20-year history of camptocormia, mild proximal weakness, and moderate CK increase. Muscle histology showed COX-negative fibres. Genetic analysis by next generation sequencing revealed an already reported heterozygous c.1192-8_1207dup24 mutation in the gene. This is the first report on a mutation leading to camptocormia as the main clinical phenotype, extending the phenotypic spectrum of associated diseases. This underlines the broad phenotypic spectrum found in mitochondrial diseases, especially in mitochondrial disorders of nuclear origin.