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Chapter 43
Inborn Metabolic Defects of Lysosomes,
Peroxisomes, Carbohydrates, Fatty Acids
and Mitochondria
Copyright © 2012, American Society for Neurochemistry. Published by Elsevier Inc. All rights reserved.
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TABLE 43-1: Lysosomal Storage Diseases
Copyright © 2012, American Society for Neurochemistry. Published by Elsevier Inc. All rights reserved.
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TABLE 43-1: Lysosomal Storage Diseases
Copyright © 2012, American Society for Neurochemistry. Published by Elsevier Inc. All rights reserved.
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TABLE 43-2: Diseases of Peroxisomal Biogenesis
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TABLE 43-3: Single Peroxisomal Enzyme Diseases
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TABLE 43-4: Clinical Features of Mitochondrial Diseases Associated with mtDNA Mutations
Copyright © 2012, American Society for Neurochemistry. Published by Elsevier Inc. All rights reserved.
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FIGURE 43-1: Electron micrograph of a Twitcher myelinated axon. The cross-section of this sciatic nerve was taken from a sick
mutant mouse and shows an axon engulfed by its Schwann cell. The cytoplasm of the myelinating Schwann cell is filled with enlarged
vacuoles and membrane structures. Crystallized deposits of undigested material, also known as Krabbe crystals, are clearly visible
(arrows). Bar: 500 nm. (Courtesy of Robert P. Becker et al., College of Medicine, University of Illinois at Chicago).
Copyright © 2012, American Society for Neurochemistry. Published by Elsevier Inc. All rights reserved.
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FIGURE 43-2: Schematic representation of glycogen metabolism and glycolysis. Roman numerals indicate the sites of identified
enzyme defects: I, glucose-6-phosphatase; II, acid maltase; III, debrancher enzyme; IV, brancher enzyme; V, muscle phosphorylase; VI,
liver phosphorylase; VII, phosphofructokinase; VIII, phosphorylase kinase; IX, phosphoglycerate kinase; X, phosphoglycerate mutase; XI,
lactate dehydrogenase; XII, aldolase; XIII, β-enolase. GLUT 1, glucose transporter; P, phosphate; PEP, phosphoenolpyruvate; PLD,
phosphorylase-limit dextrin; UDPG, uridine diphosphate glucose.
Copyright © 2012, American Society for Neurochemistry. Published by Elsevier Inc. All rights reserved.
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FIGURE 43-3: Schematic representation of fatty acid oxidation. This metabolic pathway is divided into the carnitine cycle (A), the inner mitochondrial membrane
system (B), and the mitochondrial matrix system (C). The carnitine cycle includes the plasma membrane transporter (Tp), carnitine palmitoyltransferase I (CPT I), the
carnitine–acylcarnitine translocase system (Tl) and carnitine palmitoyltransferase II (CPT II). The inner mitochondrial membrane system includes the very-long-chain
acyl-CoA dehydrogenase (VLCAD) and the trifunctional protein with three catalytically active sites. Long-chain acylcarnitines enter the mitochondrial matrix by the action
of CPT II to yield long-chain acyl-CoAs. These thioesters undergo one or more cycles of chain shortening catalyzed by the membrane-bound system. Chain-shortened
acyl-CoAs are degraded further by the matrix β-oxidation system. Medium-chain fatty acids enter the mitochondrial matrix directly and are activated to the medium-chain
acyl-CoAs before degradation by the matrix β-oxidation system. AD, acyl-CoA dehydrogenase; AS, acyl-CoA synthetase; CoA, coenzyme A; CPT, carnitine
palmitoyltransferase; EH, 2-enoyl-CoA hydratase; HD, 3-hydroxyacyl-CoA dehydrogenase; KT, 3-ketoacyl-CoA thiolase; LC, long chain; MC, medium chain; SC, short
chain; TL, carnitine-acylcarnitine translocase; Tp, carnitine transporter; VLC, very long chain. (With permission from reference Platt & Walkley, 2004.)
Copyright © 2012, American Society for Neurochemistry. Published by Elsevier Inc. All rights reserved.
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FIGURE 43-4: Schematic representation of mitochondrial metabolism. Respiratory chain complexes or components encoded
exclusively by the nuclear genome are light orange. Complexes containing some subunits encoded by the nuclear genome and others
encoded by mitochondrial DNA are dark orange. CPT, carnitine palmitoyltransferase; PDHC, pyruvate dehydrogenase complex; CoA,
coenzyme A; TCA, tricarboxylic acid; CoQ, coenzyme Q; Cyt c, cytochrome c. (Modified from reference (Conradi et al., 1984), with
permission of McGraw-Hill, New York).
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