ETFB and multiple acyl-CoA dehydrogenase deficiency: Multiple acyl-CoA dehydrogenase deficiency (MADD; OMIM, 231680) is an autosomal recessive inherited metabolic disorder mainly caused by the defects of electron transfer flavoprotein ubiquinone oxidoreductase (ETF:QO) complex encoded by the ETF dehydrogenase (ETFDH) gene, alpha ETF (ETFA) gene, and beta ETF (ETFB) gene [9].