Familial cerebellar ataxia with muscle coenzyme Q10 deficiency

TLDR

Muscle CoQ10 deficiency has been reported only in a few patients with mitochondrial encephalomyopathy characterized by recurrent myoglobinuria, brain involvement (seizures, ataxia, mental retardation), and ragged‑red fibers with lipid storage in muscle biopsies. The study aims to describe a clinical syndrome of cerebellar ataxia associated with muscle CoQ10 deficiency. After detecting reduced CoQ10 in muscle of a patient with unexplained familial cerebellar ataxia, the authors measured CoQ10 levels in muscle biopsies from additional patients lacking known genetic causes. Six patients with cerebellar ataxia, pyramidal signs, and seizures had 26–35% of normal muscle CoQ10, all of whom improved in strength, ataxia, and seizure frequency after CoQ10 supplementation, indicating primary CoQ10 deficiency is an important, treatable cause of familial ataxia.

Abstract

<b><i>Objective:</i></b> To describe a clinical syndrome of cerebellar ataxia associated with muscle coenzyme Q10 (CoQ10) deficiency. <b><i>Background:</i></b> Muscle CoQ10 deficiency has been reported only in a few patients with a mitochondrial encephalomyopathy characterized by 1) recurrent myoglobinuria; 2) brain involvement (seizures, ataxia, mental retardation), and 3) ragged-red fibers and lipid storage in the muscle biopsy. <b><i>Methods:</i></b> Having found decreased CoQ10 levels in muscle from a patient with unclassified familial cerebellar ataxia, the authors measured CoQ10 in muscle biopsies from other patients in whom cerebellar ataxia could not be attributed to known genetic causes. <b><i>Results:</i></b> The authors found muscle CoQ10 deficiency (26 to 35% of normal) in six patients with cerebellar ataxia, pyramidal signs, and seizures. All six patients responded to CoQ10 supplementation; strength increased, ataxia improved, and seizures became less frequent. <b><i>Conclusions:</i></b> Primary CoQ10 deficiency is a potentially important cause of familial ataxia and should be considered in the differential diagnosis of this condition because CoQ10 administration seems to improve the clinical picture.