Glycogen storage disease with massive left ventricular hypertrophy and increased native T1: a case report.

This case showed increased diffuse native T1 but not ECV on CMR in LGE-negative myocardium in GSD, which indicates that the T1 value is increased with an accumulation of glycogen in the myocardium, but the ECV space was not expanded in this process. Genetic testing should be obtained in severe LV hypertrophy when multi-organ involvement is present, and myocardial tissue characterization is discrepant between T1 elevation and normal ECV to consider glycogen storage disorder.