COA7 (cytochrome c oxidase assembly factor 7) is a mitochondrial protein essential for the assembly of respiratory chain complex IV (cytochrome c oxidase) 1. The protein localizes to the mitochondrial intermembrane space via the MIA pathway and functions as a heme-binding disulfide reductase that acts in the early stages of complex IV assembly 12. COA7 catalyzes the reduction of disulfide bonds within copper metallochaperones SCO1 and SCO2, which are crucial for copper relay to the COX2 subunit during complex IV biogenesis 1. Loss of COA7 blocks complex IV assembly after the initial COX1 module formation, preventing progression that requires copper incorporation and addition of COX2/COX3 modules 1. Pathogenic variants in COA7 cause spinocerebellar ataxia with axonal neuropathy type 3 (SCAN3), characterized by peripheral neuropathy, cerebellar ataxia, and in some cases dystonia or parkinsonism 34. The clinical spectrum ranges from infantile-onset generalized dystonia to progressive encephalopathy with brain atrophy, expanding beyond the typical slowly progressive neuropathy and ataxia 53. Proteasome inhibition has shown therapeutic potential by rescuing mitochondrial localization of mutant COA7 proteins and restoring complex IV activity 2.