title: Unclassified polysaccharidosis of the heart and skeletal muscle in siblings.
abstract: We describe a 15-year-old boy and his 19-year-old sister with progressive dilated cardiomyopathy and mild non-progressive proximal lower limb myopathy, secondary to the accumulation of amylopectin-like fibrillar glycogen, (polyglucosan) bodies, in heart and skeletal muscle. Evidence of idiopathic amylopectinosis or polysaccharidosis was demonstrated in heart and skeletal muscle tissue by histology, electron microscopy, biochemical, and genetic analysis. In both siblings the heart muscle stored PAS-positive, proteinase-k resistant and partly diastase resistant granulo-filamentous material, simulating polyglucosan bodies. Glycogen branching enzyme activity, and phosphofructokinase enzyme activity, measured in skeletal muscle tissue and explanted heart tissue were all within the normal limits, however glycogen content was elevated. Furthermore, GBE1, PRKAG2, desmin, alphabeta-crystallin, ZASP, myotilin, and LAMP-2 gene sequencing revealed no mutation, excluding e.g. glycogen storage disease type 4 and desmin-related myofibrillar cardiomyopathies. In both patients the diagnosis of an idiopathic polysaccharidosis with progressive dilated cardiomyopathy was made, requiring heart transplantation at age 13 and 14, respectively. Both patients belong to an autosomal recessive group of biochemically and genetically unclassified severe vacuolar glycogen storage disease of the heart and skeletal muscle. Up to now unidentified glycogen synthesis or glycogen degradation pathways are supposed to contribute to this idiopathic glycogen storage disease.
authors.affiliation: Friedrich Baur Institute, Department of Neurology, Ludwig Maximilians University of Munich, Munich, Germany. bschoser@med.uni-muenchen.de
authors.forename: Benedikt
authors.initials: B
authors.lastname: Schoser
authors.forename: Claudio
authors.initials: C
authors.lastname: Bruno
authors.forename: Hans-Christian
authors.initials: HC
authors.lastname: Schneider
authors.forename: Yoon S
authors.initials: YS
authors.lastname: Shin
authors.forename: Teodor
authors.initials: T
authors.lastname: Podskarbi
authors.forename: Lev
authors.initials: L
authors.lastname: Goldfarb
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Müller-Felber
authors.forename: Josef
authors.initials: J
authors.lastname: Müller-Höcker
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005858:Germany; D006003:Glycogen / Q000378:metabolism; D006011:Glycogen Storage Disease Type IV / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D010375:Pedigree; D035781:Siblings
chemical_list: D006003:Glycogen