3-Methylglutaconyl-Coenzyme-A Hydratase Deficiency and the Development of Dilated Cardiomyopathy.

A 25-year-old Canadian male with a history of 3-methylglutaconyl-coenzyme-A hydratase deficiency, also known as 3-methylglutaconic aciduria type I, a very rare inborn error of metabolism, presented with respiratory distress, nausea, vomiting and signs of multisystem organ failure due to a suspected underlying infectious process. An electrocardiogram revealed bilateral atrial enlargement and an elevated brain natriuretic peptide on the initial laboratory studies, which prompted a more thorough cardiac workup. The transthoracic echocardiogram revealed a dilated cardiomyopathy with severe systolic dysfunction. The deficient enzyme present in this patient is involved in the pathway of leucine catabolism and is particularly important in various tissues for energy production and sterol synthesis. The dilated cardiomyopathy in this patient possibly had a variety of potential mechanisms including: a mitochondrial myopathy due to the deficiency of this enzyme leading to a defect in energy production inside cardiac myocytes; or a direct toxicity from 3-methylglutaconic acid (3-MGA) and its toxic metabolites; or a cardiac dysfunction due to a variety of other potential mechanisms. In conclusion, this patient's clinical presentation suggested that 3-methylglutaconyl-CoA hydratase deficiency could cause a severe dilated cardiomyopathy and heart failure.