The first defect in coenzyme Q10 (ubiquinone) biosynthesis has been attributed to mutations in COQ2, encoding Para-Hydroxybenzoate-Polyprenyl Transferase. Patients with primary CoQ10 deficiency can present with myopathy, cerebellar involvement, generalized encephalopathy, and/or renal involvement. Analysis of respiratory chain enzyme activities reveal normal levels of the complexes taken individually, but low levels of complexes I+III and of complexes II+III. See article by Quinzii, C.
For more information on mitochondrial respiratory chain defects, see OMMBID Chapter 104.
Philippe Campeau, MD
Resident in Medical Genetics at McGill University
OMMBID Blog Administrator