ETFDH and multiple acyl-CoA dehydrogenase deficiency: Multiple acyl-coenzyme A (CoA) dehydrogenase deficiency (MADD, OMIN#231680), also referred to as glutaric aciduria type II, is an inherited autosomal recessive disorder characterized by defects in either electron transfer flavoprotein (ETF), which is encoded by the ETFA and ETFB genes, or ETF-ubiquinone oxidoreductase (ETF-QO), encoded by the ETFDH gene (NM_004453) [1–3].