ETFDH and multiple acyl-CoA dehydrogenase deficiency: Homozygous or compound heterozygous mutations in ETF and ETFDH are responsible for a rare inborn error of metabolism named multiple acyl‐CoA dehydrogenase deficiency (MADD) or glutaric aciduria of type II (OMIM #231680) characterized by a disorder of fatty acids and certain amino acids metabolism, abnormal acylcarnitine plasmatic profile, and secondary carnitine deficiency.