Mitochondrial dysfunction in a family with psychosis and chronic fatigue syndrome

•Mitochondrial dysfunction is associated with chronic fatigue symptoms.•Lactate stress test as an assay to identify mitochondrial impairment in CFS.•Further studies are needed to know if C16179A and T16519A alter mtDNA function.

Mitochondrial impairment is hypothesized to be involved in chronic fatigue syndrome (CFS) and schizophrenia. We performed a clinical, genetic and functional mitochondrial study in a family consisting of a female presenting schizophrenia in addition to CFS symptoms and her mother and older sister, both presenting with CFS. The three family members showed higher blood lactate levels, higher mitochondrial mass, lower mtDNA content and overall lower mitochondrial enzymatic activities and lower oxygen consumption capacities than healthy women. This family presented mtDNA depletion; however, no mutation was identified neither in the mtDNA nor in the nuclear genes related with mtDNA depletion, even though C16179A and T16519A variants should be further studied.