Interestingly, the last few years a number of riboflavin transporter genes (SLC52A1, SLC52A2, SLC52A3) [112,113,114], mitochondrial flavin adenine dinucleotide (FAD) transporter gene (SLC25A32) [115] and FAD synthetase gene (FLAD1) [116] have been linked to undiagnosed cases of riboflavin-responsive MADD. Here, FLAD1 is linked to multiple acyl-CoA dehydrogenase deficiency.