Mitochondrial Complex I Deficiency, Nuclear Type 20, also known as acyl-coa dehydrogenase 9 deficiency, is related to leigh syndrome and hypoglycemia, and has symptoms including muscle weakness An important gene associated with Mitochondrial Complex I Deficiency, Nuclear Type 20 is ACAD9 (Acyl-CoA Dehydrogenase Family Member 9), and among its related pathways/superpathways are Metabolism and Respiratory electron transport, ATP synthesis by chemiosmotic coupling, and heat production by uncoupling proteins.. The drug Pyruvate has been mentioned in the context of this disorder. Affiliated tissues include liver and heart, and related phenotypes are decreased activity of mitochondrial complex i and failure to thrive