Mitochondrial Complex Iii Deficiency, Nuclear Type 4, also known as mitochondrial complex iii deficiency nuclear type 4, is related to leigh syndrome, and has symptoms including ataxia, athetosis and abnormality of extrapyramidal motor function. An important gene associated with Mitochondrial Complex Iii Deficiency, Nuclear Type 4 is COX10 (Cytochrome C Oxidase Assembly Factor Heme A:Farnesyltransferase COX10). Affiliated tissues include eye and liver, and related phenotypes are hyperreflexia and failure to thrive