We assessed the clinical outcome after
coenzyme Q(10) (
CoQ(10))
therapy in 14 patients presenting
ataxia classified into two groups according to
CoQ(10) values in muscle (deficient or not). We performed an open-label prospective study: patients were evaluated clinically (international cooperative
ataxia rating scale [ICARS] scale, MRI, and videotape registration) at baseline and every 6 months during a period of 2 years after
CoQ(10) treatment (30 mg/kg/day). Patients with
CoQ(10) deficiency showed a statistically significant reduction of ICARS scores (Wilcoxon test: P = 0.018) after 2 years of
CoQ(10) treatment when compared with baseline conditions. In patients without
CoQ(10) deficiency, no statistically significant differences were observed in total ICARS scores after
therapy, although 1 patient from this group showed a remarkable clinical amelioration. Biochemical diagnosis of
CoQ(10) deficiency was a useful tool for the selection of patients who are good candidates for treatment as all of them responded to
therapy. However, the remarkable clinical response in 1 case without
CoQ(10) deficiency highlights the importance of treatment trials for identification of patients with CoQ(10)-responsive
ataxia.