The efficacy of coenzyme Q 10 treatment in alleviating the symptoms of primary coenzyme Q 10 deficiency: A systematic review.

Coenzyme Q 10 (CoQ 10 ) is necessary for mitochondrial electron transport. Mutations in CoQ 10 biosynthetic genes cause primary CoQ 10 deficiency (PCoQD) and manifest as mitochondrial disorders. It is often stated that PCoQD patients can be treated by oral CoQ 10 supplementation. To test this, we compiled all studies describing PCoQD patients up to May 2022. We excluded studies with no data on CoQ 10 treatment, or with insufficient description of effectiveness. Out of 303 PCoQD patients identified, we retained 89 cases, of which 24 reported improvements after CoQ 10 treatment (27.0%). In five cases, the patient's condition was reported to deteriorate after halting of CoQ 10 treatment. 12 cases reported improvement in the severity of ataxia and 5 cases in the severity of proteinuria. Only a subjective description of improvement was reported for 4 patients described as responding. All reported responses were partial improvements of only some symptoms. For PCoQD patients, CoQ 10 supplementation is replacement therapy. Yet, there is only very weak evidence for the efficacy of the treatment. Our findings, thus, suggest a need for caution when seeking to justify the widespread use of CoQ 10 for the treatment of any disease or as dietary supplement.