The biochemical characterization of a missense mutation m.8914C>T in ATP6 gene associated with mitochondrial encephalomyopathy

•Missense mutations in ATP6 gene were commn causes of mitochondrial encephalomyopathies.•We found a novel missense mutation in ATP6 gene (m.8914C>T) associated with mitochondrial encephalomyopathy.•The mutation load in blood sample of patient is 59.49%.•Activity of complexes in blood was normal, but the function of mitochondrial oxidative phosphorylation was declined.•The m.8914C>T in ATP6 gene was related with dysfunction of complexV.