Reversing Acute Cardiomyopathy With Coenzyme Q10 Supplementation in Cobalamin B Disease: A Case Report and Literature Review.

Methylmalonic acidemia (MMA) is a rare metabolic disorder with various subtypes, including Cobalamin B (cblB) disease. While cardiac complications are well-documented in propionic acidemia, their occurrence in MMA is less understood. Here, we report a 12-year-old child with cblB disorder who developed acute cardiomyopathy (CM). The patient presented with fever, tachycardia, and dyspnea. Echocardiography revealed depressed left ventricular function, which initially improved with standard treatment but rapidly deteriorated. Coenzyme Q10 (CoQ10) supplementation was initiated at a dose of 25 mg/kg/day, resulting in a remarkable improvement in cardiac function within 72 h. This report highlights the potential efficacy of CoQ10 in treating MMA-related cardiomyopathy, suggesting mitochondrial dysfunction as a key factor. The successful use of CoQ10 in this context is novel, as previous literature mainly focused on its application in propionic acidemia. This report proposes CoQ10 supplementation as a promising adjuvant therapy for cardiomyopathy in MMA, particularly in cblB disorder, and calls for further research to validate its benefits.