A disorder of fatty acid and amino acid oxidation, caused by mutations in ETFDH, ETFA, or ETFB, and is a clinically heterogeneous disorder ranging from a severe neonatal presentation with metabolic acidosis, cardiomyopathy and liver disease, to a mild childhood/adult disease with episodic metabolic decompensation, muscle weakness, and respiratory failure. The disease is Monarch Disease Ontology entry MONDO_0009282 (multiple acyl-CoA dehydrogenase deficiency). Also known as: Glutaric Aciduria Type II, MAD deficiency, MADD, electron transfer flavoprotein deficiency, electron transfer flavoprotein ubiquinone oxidoreductase deficiency, glutaric acidemia type 2, glutaric acidemia type II, glutaric aciduria type 2.