Riboflavin (B2) and FAD/FMN Metabolites

Riboflavin (vitamin B2) is a water-soluble vitamin and is the precursor in the synthesis of Flavin Mononucleotide (FMN) and Flavin Adenine Dinucleotide (FAD), which are essential for aerobic metabolism. Riboflavin-related inborn errors comprise genetic defects in riboflavin transport and intracellular riboflavin metabolism. More frequently, restricted diets, especially diets without dairy, may cause a nutritional riboflavin deficiency. Flavin levels (riboflavin, FAD, and FMN) are generally measured by HPLC fluorescence-based methods. In this chapter, a HPLC fluorescence-based method is described in detail, and reference values and interpretation of decreased flavin levels are provided.