Defects in this gene have very recently been associated with severe and rapidly progressive encephalopathy with neonatal or infantile onset and associated with cardiomyopathy, oculomotor apraxia and peripheral neuropathy.24,25 In the present study, patients carrying deleterious variants in COX18 exhibit as a cardinal feature progressive sensorimotor polyneuropathy of variable onset, and some of them also display signs of CNS involvement. Here, COX18 is linked to peripheral neuropathy.