Coenzyme Q10 and vitamin E deficiency in Friedreich’s ataxia: predictor of efficacy of vitamin E and coenzyme Q10 therapy


Dr J. M. Cooper, University Department of Clinical Neurosciences, Institute of Neurology, University College London, Rowland Hill Street, London NW3 2 PF, UK (tel.: +44 02074726604; fax: +44 02074726829; e-mail:


Background and purpose:  A pilot study of high dose coenzyme Q10 (CoQ10)/vitamin E therapy in Friedreich’s ataxia (FRDA) patients resulted in significant clinical improvements in most patients. This study investigated the potential for this treatment to modify clinical progression in FRDA in a randomized double blind trial.

Methods:  Fifty FRDA patients were randomly divided into high or low dose CoQ10/ vitamin E groups. The change in International Co-operative Ataxia Ratings Scale (ICARS) was assessed over 2 years as the primary end-point. A post hoc analysis was made using cross-sectional data.

Results:  At baseline serum CoQ10 and vitamin E levels were significantly decreased in the FRDA patients (P < 0.001). During the trial CoQ10 and vitamin E levels significantly increased in both groups (P < 0.01). The primary and secondary end-points were not significantly different between the therapy groups. When compared to cross-sectional data 49% of all patients demonstrated improved ICARS scores. This responder group had significantly lower baseline serum CoQ10 levels.

Conclusions:  A high proportion of FRDA patients have a decreased serum CoQ10 level which was the best predictor of a positive clinical response to CoQ10/vitamin E therapy. Low and high dose CoQ10/vitamin E therapies were equally effective in improving ICARS scores.