ETFDH and multiple acyl-CoA dehydrogenase deficiency: MADD, also known as Glutaric Acidemia Type II, is an autosomal recessive genetic disorder caused by mutations in the Electron Transfer Flavoprotein (ETFA, ETFB) or Electron Transfer Flavoprotein Dehydrogenase (ETFDH) genes, encoding for the α and β subunits of Electron Transfer Flavoprotein (ETF) and Electron Transfer Flavoprotein-Ubiquinone Oxidoreductase (ETF-QO) [31].