Background:
Primary deficiency of coenzyme Q10 deficiency-4 (CoQ10D4) is a heterogeneous disorder affecting different age groups. The main clinical manifestation consists of cerebellar ataxia, exercise intolerance, and dystonia.
Case report:
We provide a case of adolescence-onset ataxia, head tremor, and proximal muscle weakness accompanied by psychiatric features and abnormal serum urea (49.4 mg/dL), lactate (7.5 mmol/L), and CoQ10 level (0.4 µg/mL). Brain-MRI demonstrated cerebellar atrophy, thinning of the corpus callosum, and loss of white matter. Whole exome sequencing showed a homozygous missense mutation (c.911C>T; p.A304V) in CoQ8A gene which is a rare mutation and responsible variant of CoQ10D4. After supplementary treatment with CoQ10 50 mg/twice a day for 2 months the clinical symptoms improved.
Conclusion:
These observations highlight the significance of the early diagnosis of potentially treatable CoQ8A mutation as well as patient education and follow-up. Our findings widen the spectrum of CoQ8A phenotypic features so that clinicians be familiar with the disease not only in severe childhood-onset ataxia but also in adolescence with accompanying psychiatric problems.