Early-onset fatal encephalomyopathy associated with severe mtDNA depletion.

UNLABELLED: We studied a 3-month-old girl who was admitted to hospital because of respiratory distress. The clinical course was characterized by a rapidly progressive generalized hypotonia with lactic acidosis and she died at 4 months of age. A muscle biopsy showed few ragged-red fibres and lack of histochemical cytochrome c oxidase reaction in all fibres. Enzyme activities of the respiratory chain complexes containing subunits encoded by the mitochondrial DNA (mtDNA) were markedly decreased. A quantitative Southern blot analysis revealed 99% depletion of mtDNA in muscle and normal amounts in blood. There was no family history and the dizygotic twin sister of the patient was no symptomatic.

CONCLUSION

This new case confirms the rapidly fatal evolution associated with severe depletion of muscle mtDNA.