A Case of Late Onset Riboflavin-responsive Multiple Acyl-CoA Dehydrogenase Deficiency Manifesting as Recurrent Rhabdomyolysis and Acute Renal Failure

We report an adult case of late-onset riboflavin-responsive multiple acyl-CoA dehydrogenase deficiency (MADD) characterized by episodic recurrent rhabdomyolysis and acute renal failure after the age of 46. Muscle biopsy revealed lipid storage myopathy and the finding of serum acylcarnitine and urine organic acid analyses were consistent with MADD. A compound heterozygous mutation was identified in the electron-transferring-flavoprotein dehydrogenase (ETFDH) gene, including a novel missense mutation, which confirmed the diagnosis of MADD. After administration of riboflavin and L-carnitine, the muscle weakness and fatigability gradually improved. Acylcarnitine and urine organic acid were also normalized after supplementation. Thus, MADD should be included in one of the differential diagnoses for adult recurrent rhabdomyolysis. Gene analysis is useful to confirm the diagnosis, and early diagnosis is important because riboflavin treatment has been effective in a significant number of patients with MADD.