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

To report on a case with a mitochondrial DNA (mtDNA) depletion syndrome.Laboratory studies were done in muscle biopsy and fibroblasts to evaluate coenzyme Q(10) (CoQ(10)) status and quantify mitochondrial DNA.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.mtDNA depletion syndrome was associated with CoQ(10) deficiency in our patient.