These factors afford stability of newly synthesized COX2 (the dystonia-ataxia syndrome protein COX20), a protein with two transmembrane domains, and maturation of its copper center, Cu<sub>A</sub> (cardiomyopathy proteins SCO1, SCO2, and COA6).
In conclusion, we extend the phenotypic spectrum of a recently identified mutation in COX20 to a recessively inherited, early-onset dystonia-ataxia syndrome that is characterized by reduced complex IV activity.