Mitochondrial complex IV deficiency
Cytochrome-c oxidase deficiency
Type of disease: Rare conditions
COX deficiency is a mitochondrial disease that is caused by the lack of the cytochrome C oxidase (COX) enzyme. Enzymes are special proteins that facilitate all of the biochemical reactions in our bodies. COX is an essential enzyme that is active in mitochondria, specialized compartments in our cells that produce almost all of the energy needed by the body. The process by which mitochondria make energy is very complex and involves multiple steps that use many different enzymes, including COX. The lack of COX causes a ‘traffic jam’ in this process, and the defective mitochondria cannot produce enough energy for the cells to function properly. Nearly all our cells rely on mitochondria for a steady energy supply, so COX deficiency can affect many parts of the body. There are several types of COX deficiency, but all share some similar symptoms. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.