Glycogen Storage Mimicking Arrhytmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C)
ER Rodriguez, CD Tan. Cleveland Clinic, Cleveland, OH
Background: Glycogen storage in the heart can occur when the AMP-dependent protein kinase subunit 2 (PRKAG2) gene is mutated. These patients commonly present with hypertrophic cardiomyopathy and diverse types of arrhythmias, including: preexcitation (Wolff-Parkinson-White syndrome; WPW), atrial fibrillation, and progressive atrioventricular block. In contrast arrhythmogenic right ventricluar dysplasia/cardiomyopathy (ARVD/C) is a disease that affects primarily the right ventricle, producing marked thinning of its free wall. This thinning of the wall shows adipose tissue infiltration and fibrosis which replace the cardiac muscle. These patients present with multiple arrhytmias or sudden death.
Design: A database of clinical features and results of pathologic examination reports was reviewed for the period January 1, 2006 to September 11, 2008. A total of 180 heart transplants were performed during this period. Age, gender and final pathologic diagnoses of hypertrophic cardiomyopathy (HCM) or ARVD/C were included in this study.
Results: Eight of 180 patients were identified as having HCM and/or ARVD/C. There were 3 males and 5 females. The average age was 49 years. Six patients had clinical diagnosis of HCM, 3 of which were proven histologically. The other 3 showed marked vacuolation of myocytes with sarcoplasmic eosinophilic inclusions which stained positive with PAS and showed excess glycogen on electron microscopy. Two patients had clinical diagnosis of ARVD, one of which showed marked hypertrophy of the left ventrcle and vacuolation of myocytes as described above. Thus a total of 4 patients showed glycogen storage, 2 of these 4 had mutations in the PRKAG2 gene. In addition, these two latter patients showed paper thin translucent right ventricular free walls and right ventricular outflow tract with loss of myocytes and fibro-fatty infiltration, confirmed by microscopic examination. Furthermore, these same 2 patients also had clinical histories of arrhytmias. There was only 1 patient with isolated ARVD/C by pathologic and clinical criteria.
Conclusions: This is the first report with clinico-pathologic and genetic confirmation of PRKAG2 glycogen storage mimicking ARVD/C. Glycogen storage disease is known to mimic hypertrophic cardiomyopathy. This study shows that glycogen storage diseease secondary to PRKAG2 mutation can mimic ARVD/C both, clinically and morphologically.
Tuesday, March 10, 2009 1:00 PM
Poster Session IV # 50, Tuesday Afternoon