Coenzyme Q10 deficiency associated with a mitochondrial DNA depletion syndrome: a case report.

OBJECTIVES: To report on a case with a mitochondrial DNA (mtDNA) depletion syndrome. DESIGN AND METHODS: Laboratory studies were done in muscle biopsy and fibroblasts to evaluate coenzyme Q(10) (CoQ(10)) status and quantify mitochondrial DNA. RESULTS: Decreased CoQ(10) values and a 78% of mtDNA depletion were detected in muscle. Mutational studies failed to reveal any pathogenic mutation in nuclear genes related with mtDNA maintenance. CONCLUSIONS: mtDNA depletion syndrome was associated with CoQ(10) deficiency in our patient.