A case of respiratory muscle weakness due to cytochrome c oxidase enzyme deficiency.

Mitochondrial myopathy is a rare cause of dyspnoea and respiratory failure, usually presenting in infancy. We describe a 27 yr old woman with a partial cytochrome c oxidase enzyme deficiency causing respiratory muscle weakness and respiratory failure. The onset was acute, with no preceding respiratory symptoms. The patient was successfully treated with bilevel positive airway pressure therapy.