Paternal Inheritance of Mitochondrial DNA

This report describes a 28-year-old man with lifelong exercise intolerance. Evaluation revealed a mitochondrial myopathy due to a novel 2-bp mitochondrial DNA deletion in the ND2 gene, which codes for a subunit of enzyme complex I of the mitochondrial respiratory chain. Studies of the patient and his immediate family members revealed that the abnormal mitochondrial DNA was paternal in origin and accounted for 90 percent of the mitochondrial DNA in the patient's muscle.