A mitochondrial complex III deficiency characterized by onset in early childhood of episodic acute lactic acidosis, ketoacidosis, and insulin-responsive hyperglycemia, usually associated with infection and that has_material_basis_in homozygous mutation in the CYC1 gene on chromosome 8q24. [ url:http://omim.org/entry/615453?search=615453&highlight=615453 http://purl.obolibrary.org/obo/ECO_0007636 ]