COQ8A and major depressive disorder: ADCK3 is the homologue of the yeast Coq8 gene and encodes a mitochondrial protein which functions in an electron-transferring membrane protein complex in the MRC.8 Patients with ADCK3 mutations usually have disease onset in infancy or early childhood and can present with pure cerebellar ataxia or a complex phenotype with additional features, such as seizures, cognitive impairment, depression, peripheral neuropathy, strabismus or exercise intolerance.8–11