This FAD supplementation was previously reported to correspond to the increase in FAD content in muscle mitochondria after riboflavin supplementation in patients with multiple acyl-CoA dehydrogenase deficiency (MADD), which also rescued electron transfer flavoprotein (ETF) deficiencies in vitro [27,28]. This evidence concerns the gene TEAD2 and multiple acyl-CoA dehydrogenase deficiency.