amylopectin and Cardiomyopathies

We report a 17-month-old female patient with a rare cause of cardiomyopathy secondary to accumulation of amylopectin-like material (fibrillar glycogen) isolated to the heart. Evidence of amylopectinosis isolated to cardiac myocytes in this patient was demonstrated by histology and electron microscopy. Glycogen content, glycogen branching enzyme (GBE) activity, as well as phosphofructokinase enzyme activities measured in liver, skeletal muscle, fibroblasts and ex-transplanted heart tissue were all in the normal to lower normal ranges. Normal skeletal muscle and liver tissue histology and GBE activity, normal GBE activity in skin fibroblasts, plus normal GBE gene sequence in this patient exclude the classical branching enzyme deficiency (type IV GSD). We believe that this is an as yet uncharacterized and novel phenotype of GSD associated with cardiomyopathy, in which there is an imbalance in the regulation of glycogen metabolism limited to the heart.

Topics: 1,4-alpha-Glucan Branching Enzyme; Amylopectin; Cardiomyopathies; Electrocardiography; Female; Fibroblasts; Glycogen Storage Disease Type IV; Humans; Infant; Ventricular Dysfunction, Left

Orthotopic liver transplantation (OLT) has been proposed to treat patients with type IV glycogenosis because of early progressive cirrhosis. Reports have shown absence of disease progression in other organs after OLT and even regression of cardiac amylopectin infiltration in one case. We describe a 15-month-old child in whom a liver transplant was performed for type IV glycogenosis. There were no clinical signs of extrahepatic disease before OLT. Nine months later, the patient developed progressive cardiac insufficiency and died from cardiac failure. Because of massive amylopectin deposits, decreased myofibrils in cardiac cells, and exclusion of other causes of cardiac failure, death was attributed to amylopectionosis. Our observation contrasts with the Pittsburgh experience and suggests that cardiac amylopectionosis may progress after OLT.

Topics: Amylopectin; Biopsy; Cardiomyopathies; Cardiomyopathy, Dilated; Glycogen Storage Disease Type IV; Humans; Infant; Liver; Liver Transplantation; Male; Microscopy, Electron; Myocardium

Topics: Amylopectin; Biopsy; Cardiomyopathies; Cell Nucleus; Child; Child, Preschool; Cytoplasm; Female; Glucosidases; Glucosyltransferases; Glycogen Storage Disease; Glycogen Storage Disease Type I; Hepatomegaly; Humans; Infant; Liver; Liver Diseases; Microscopy, Electron; Muscles; Muscular Diseases; Syndrome