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.