Glycogen Storage Disease Type III: The Critical Role of Cardiac MRI in Detecting Insidious Progression.

Glycogen storage disease type III (GSDIII) is a metabolic disorder characterized by glycogen accumulation in tissues, such as the liver, skeletal muscle, and myocardium. While cardiac involvement is rare, it can result in serious complications including cardiomyopathy and arrhythmias. The cardiac manifestations of GSDIII have been scarcely reported. This case demonstrates the role of cardiac MRI in evaluating myocardial involvement in a patient with GSDIII, highlights the progression of myocardial changes over a 2-year follow-up period, and finds two novel heterozygous AGL mutations, expanding the spectrum of known AGL mutation in Chinese patients with GSDIII. Keywords: Cardiac, MR-Imaging, Myocardium Supplemental material is available for this article. © RSNA, 2025.