Ultrastructure of heart muscle in generalized gangliosidosis GM1

Abstract

Abstract. Generalized gangliosidosis G~I is characterized by the almost complete deficiency of the enzyme fl-galaetosidase, therefore the cleavage of the terminal galactose from the gangliosid GM1 is impaired.Typical alterations could be observed in generalized gangliosidosis GMj in heart muscle cells as well as in capillary endothelium, and nerve fibers. Large vacuoles, containing granular or floccu]ent material and inclusion bodies, were obvious. Key-Words:Inborn Errors of Metabolism --Generalized Gangliosidosis G~I --Ultrastrueture of Heart Muscle.Zusammen/assung. Die generalisierte Gangliosidose G~ 1 ist durch einen erheblichen bzw. vollstEndigen Mangel des Enzyms fi-Galactosidase gekennzeichnet. Die Spaltung der endstEndigen Galaetosemolekiile vom Gangliosid GM1 ist deshalb blockiert. Es werden die VerEnderungen der Herzmuskelzellen, der Capillarendothelien und der vegetativen Nervenfasern besehrieben. GroBe Vacuolen mit einem feinflockigen Inhalt und EinsehluBkSrper stellen die wesentlichen Befunde dar.Generalized gangliosidosis G~I is believed to be of autosomal-recessive inheritance [3,5,10]. This metabolic disorder is characterized by the almost complete deficiency of fi-galactosidase [2,7,8]. Therefore the cleavage of the terminal galactose from the gangliosid G~I is impaired [4,7]. Besides, this enzymatic defect causes an excessive accumulation of the ganglioside GM1 in the central nervous system and in visceral organs [5], A keratan sulfate-hke mueopolysaccharide which contains galactose and hexosamine is stored in visceral organs, too [6,11]. From * This study was supported by a grant from the Deutsche Forschungsgemeinschaft.Abbreviations used: A = axon; BW = interstitial cell; D = dense body; E = endothelium; EDI = electron-dense inclusion body; IB = inclusion body; G = granule; L = lumen; M = heart muscle cell; Mi = mitochondria; mf = myofiber; Va ~ vacuole.

Generalized gangliosidosis type II (Juvenile GM1 gangliosidosis)

“…Unlike the myocardial involvement in GM 1 gangliosidosis type I [21,22], the myocardial cells of ours and other reported eases of GM 1 gangliosidosis type 2 do not appear to contain storage material. In our 3 eases, the mitral and aortic valve leaflets were strikingly deformed, thickened and retracted, and contained an abundance of storage material.…”