Monarch Disease Ontology entry MONDO_0000863 (myopathy, lactic acidosis, and sideroblastic anemia) is mitochondrial myopathy and sideroblastic anemia belongs to the heterogeneous family of metabolic myopathies. It is characterized by progressive exercise intolerance manifesting in childhood, onset of sideroblastic anemia around adolescence, lactic acidaemia, and mitochondrial myopathy. Also known as: MLASA, MSA, mitochondrial myopathy and sideroblastic anaemia, mitochondrial myopathy and sideroblastic anemia, myopathy, lactic acidosis and sideroblastic anaemia, myopathy, lactic acidosis and sideroblastic anemia, myopathy, lactic acidosis, and siderblastic anaemia, myopathy, lactic acidosis, and siderblastic anemia.