Delayed diagnosis of fatal medium-chain acyl-CoA dehydrogenase deficiency in a child

A 5-year-old white female presented with coma and died unexpectedly. She had a history of recurrent episodes of febrile illnesses associated with lethargy and coma. Postmortem investigation revealed a fatty liver, leading to a suspicion of inborn error of fatty acid oxidation. The diagnosis of medium-chain acyl-CoA dehydrogenase (MCAD) deficiency was suggested by abnormal acylcarnitine profile with increased octanoylcarnitine in the blood, and confirmed by fatty acid oxidation studies and mutation analysis in skin fibroblast cultures. This case emphasizes the need to consider fatty acid oxidation disorders in all children who present with hypoglycemia with absent or mild ketones in the urine and high anion gap metabolic acidosis.