FMN1 and hyperinsulinemic hypoglycemia, familial, 4: While FAD showed little therapeutic efficacy in our experimental system, its activity has been associated with metabolic diseases, such as multiple acyl‐coenzyme A dehydrogenase deficiency and hepatic steatosis.[18] On the other hand, FMN has additional roles in generating ATP and NADH, which are novel regulators of calcium homeostasis, mitochondrial functions, and aging.[19] Therefore, additional research is needed to clarify the distinct roles of FMN cofactors in neurodegenerative diseases.