COXIII mutations have mainly been associated with colon and thyroid cancer (https://www.mitomap.org/foswiki/bin/view/MITOMAP/MutationsSomatic) (accessed on 23 September 2021) and suggested to cause an overproduction of superoxide anions by the mitochondrial respiratory chain at COX deficiency [51]. Here, MT-CO3 is linked to mitochondrial complex IV deficiency, nuclear-type.