glycogen and Fabry-Disease

Ultrastructural and histochemical studies of bioptic and postmortem tissue samples from ten Fabry hemizygotes showed lysosomal storage in adipocytes as a constant feature of the classic phenotype of α-galactosidase (GLA) deficiency. The storage was represented by a crescent-shaped line of storage lysosomes of varying thicknesses restricted to the perinuclear subplasmalemmal area. The ultrastructure of the storage lysosomes was dominated by concentric lipid membranes modified by simultaneous deposition of autofluorescent ceroid. Storage was widely expressed in adipose tissue. The number of storage lysosomes was increased, and the lysosomes were more clustered in adipocytes with less voluminous lipid content. The findings should attract interest to studies of adipose tissue biology in Fabry disease, a topic that has not been studied so far. In terms of cell biology, the observations represent indirect evidence of significant lysosomal turnover of α-galactose lipid conjugates in adipocytes demasked by GLA deficiency. The results extend the thus far limited information on the adipocyte lysosomal system and its participation in lysosomal storage disorders.

Topics: Adipocytes; alpha-Galactosidase; Autopsy; Biopsy; Fabry Disease; Genetic Predisposition to Disease; Glycogen; Hemizygote; Humans; Lysosomes; Male; Mutation; Phenotype

Unexplained left ventricular hypertrophy often prompts the diagnosis of hypertrophic cardiomyopathy, a sarcomere-protein gene disorder. Because mutations in the gene for AMP-activated protein kinase gamma2 (PRKAG2) cause an accumulation of cardiac glycogen and left ventricular hypertrophy that mimics hypertrophic cardiomyopathy, we hypothesized that hypertrophic cardiomyopathy might also be clinically misdiagnosed in patients with other mutations in genes regulating glycogen metabolism.. Genetic analyses performed in 75 consecutive unrelated patients with hypertrophic cardiomyopathy detected 40 sarcomere-protein mutations. In the remaining 35 patients, PRKAG2, lysosome-associated membrane protein 2 (LAMP2), alpha-galactosidase (GLA), and acid alpha-1,4-glucosidase (GAA) genes were studied.. Gene defects causing Fabry's disease (GLA) and Pompe's disease (GAA) were not found, but two LAMP2 and one PRKAG2 mutations were identified in probands with prominent hypertrophy and electrophysiological abnormalities. These results prompted the study of two additional, independent series of patients. Genetic analyses of 20 subjects with massive hypertrophy (left ventricular wall thickness, > or =30 mm) but without electrophysiological abnormalities revealed mutations in neither LAMP2 nor PRKAG2. Genetic analyses of 24 subjects with increased left ventricular wall thickness and electrocardiograms suggesting ventricular preexcitation revealed four LAMP2 and seven PRKAG2 mutations. Clinical features associated with defects in LAMP2 included male sex, severe hypertrophy, early onset (at 8 to 17 years of age), ventricular preexcitation, and asymptomatic elevations of two serum proteins.. LAMP2 mutations typically cause multisystem glycogen-storage disease (Danon's disease) but can also present as a primary cardiomyopathy. The glycogen-storage cardiomyopathy produced by LAMP2 or PRKAG2 mutations resembles hypertrophic cardiomyopathy but is distinguished by electrophysiological abnormalities, particularly ventricular preexcitation.

Topics: Adolescent; Adult; Aged; Algorithms; AMP-Activated Protein Kinases; Antigens, CD; Cardiomyopathy, Hypertrophic; Child; Diagnosis, Differential; Electrocardiography; Fabry Disease; Female; Glycogen; Glycogen Storage Disease; Glycogen Storage Disease Type II; Humans; Hypertrophy, Left Ventricular; Lysosomal Membrane Proteins; Lysosomal-Associated Membrane Protein 2; Male; Middle Aged; Multienzyme Complexes; Mutation; Myocardium; Pedigree; Protein Serine-Threonine Kinases

A sural nerve biopsy of a patient with Fabry's disease showed depletion of larger myelinated fibres, but smaller myelinated and unmyelinated fibres were intact. Epineurial and to a lesser degree endoneurial vessels revealed abundant lamellar inclusions in the endothelial and perithelial cells. Larger myelinated nerve fibres contained glycogen granules in the vacuoles caused by splitting of the adaxonal membranes. A skin biopsy revealed abundant inclusions in the secretory cells and myoepithelial cells of the sweat glands. The lumen of the gland was packed with inclusions like those in the vessel walls. The pain and anhydrosis might be caused by accumulation of glycolipid in the vasa nervorum and sweat glands and not by autonomic nerve involvement.

Topics: Adult; Axons; Endothelium; Fabry Disease; Glycogen; Glycolipids; Humans; Male; Nerve Fibers, Myelinated; Peripheral Nerves; Skin; Sural Nerve