Diseases mucopolysaccharidoses

Amyloidosis, fatty liver, glycogenoses, Wolman s syndrome, hyperchylomicronaemia, Wilson s disease, Zellweger s cerebrohepato renal syndrome, Niemann-Pick disease, mucopolysaccharidoses, etc. 

Keratan sulfate an acidic mucopolysaccharide composed of N-acetyl-o-glucosamine 6-sulfate and D-galactose, linked alternately by P-1,3 and P-1,4 glyco-sidic bonds. K.s. is found in the cornea of the eye, in cartilage, in the aorta and in intervertebral discs. For formula, see Lysosomal storage diseases (Mucopolysaccharidoses). 

The term mucolipidosis was introduced to denote diseases that combined features common to both mucopolysaccharidoses and sphingolipidoses (Chapter 24). Three mucolipidoses are listed in Table 48—7. In sialidosis (mucolipidosis I, ML-I), various oligosaccharides derived from glycoproteins and certain ganglio-sides can accumulate in tissues. I-cell disease (ML-II)... 

Scriver CR et al (editors) The Metabolic and Molecular Bases of Inherited Disease, 8th ed. McGraw-Hill, 2001 (This comprehensive four-volume text contains chapters on disorders of collagen biosynthesis and structure, Marfan syndrome, the mucopolysaccharidoses, achondroplasia, Alport syndrome, and craniosynostosis syndromes.)... 

Neufeld EF, Muenzer J (2001) The mucopolysaccharidoses. In Scriver CR, Sly WS, Childs B, Beaudet AL, Valle D, Kinzler KW, Vogelstein (eds) The Metabolic and Molecular Basis of Inherited Disease, 8th edn. McGraw-Hill, New York, pp 3421-3452... 

Genetic defects in the degradation of glycoproteins are representative of lysosomal storage disorders. Each disease is caused by a deficiency of a lysosomal hydrolase, accumulation and urinary excretion of substrates, a progressive clinical course and considerable phenotypic variation. These disorders also manifest the clinical symptoms normally associated with genetic mucopolysaccharidoses, namely coarse facies, dysostosis multiplex and/or ocular involvement. 

Mucopolysaccharidoses are inherited storage diseases. They are caused by ... 

Correct answer = C. In mucopolysaccharidoses, synthesis of proteoglycans is unaffected, both in terms of the structure and the amount of material synthesized. The diseases are caused by a deficiency of one of the lysosomal, hydrolytic enzymes responsible for the degradation of glycosaminogly-cans (not the core protein). 

Sulfotransferases917 920a transfer sulfo groups to O and N atoms of suitable acceptors (reaction type ID, Table 10-1). Usually, transfer is from the "active sulfate," 3 -phosphoadenosine 5 -phosphosuIfate (PAPS),921 whose formation is depicted in Eq. 17-38. Sulfatases catalyze hydrolysis of sulfate esters. The importance of such enzymes is demonstrated by the genetic mucopolysaccharidoses. In four of these disease-specific sulfatases that act on iduronate sulfate, heparan N-sulfate, galactose-6-sulfate, or N-acetylglu-cosamine-4-sulfate are absent. Some of these, such as heparan N-sulfatase deficiency, lead to severe mental retardation, some cause serious skeletal abnormalities, while others are mild in their effects.922... 

Lysosomal storage abnormalities, such as glycogenosis (Pompe s disease). Tay-Sachs, Krabbe s. Gaucher s, and Fabry s diseases, as well as melachromatic leukodystrophy, aspariylgiycosaminuria, and Niemann-Pick disease. Also included in this category are mucopolysaccharidoses. Hunter s, Scheie s, and Hurler s syndromes. 

Gaucher disease, and Krabbe disease. LSDs are classified as mucopolysaccharidoses (MPS), lipidoses, or mucolipidoses depending on the nature of the stored material. Over 40 LSDs are known and they have a collective incidence of approximately 1 in 7000-8000 live births (Meikle et al., 1999 Poorthuis et al., 1999 Winchester et al., 2000). Most of the genes for these lysosomal proteins have been cloned, permitting mutation analysis in individual cases. 

Analysis of urine for excess substrates (e.g., glycosaminoglycans in the Mucopolysaccharidoses, globotriaolsylceramide in Fabry disease) may also suggest the presence of an LSD. In any case, all patients suspected to have an LSD should have diagnostic confirmation by means of biochemical and/or molecular genetic analysis. 

F-1) The mucopolysaccharidoses are proteoglycan disorders that generally result from a hereditary lysosomal defect in enzymes that normally degrade mucopolysaccharides (in most cases heparan sulfate and dermatan sulfate). This leads to the accumulation of different mucopolysaccharides, which may be associated with a variety of different findings, commonly including mental retardation and various skeletal abnormalities. These diseases include Hunter disease, Hurler and Scheie disease, I-cell disease , Maroteaux-Laury disease, Morquio syndrome, Mucolipidoses VH disease, multiple sulfatase deficiency, and Sanfilippo A and B diseases, which will not be elaborated on further here. Often these conditions can be detected in advance on amniocentesis. 

Excessive accumulation of proteins, nucleic acids, carbohydrates, and lipids can result from deficiency of one or more lysosomal hydrolases. Lysosomal storage diseases are classified by the stored material. Accumulation of gly-cosaminoglycans results in mucopolysaccharidoses. Common causes of this disorder include Hunter syndrome, Hurler syndrome, and Sanfihppo syndrome. Sanfdippo syndrome is inherited in an autosomal recessive pattern and clinically evident by profound mental retardation, lack of normal developmental milestones, and significant language delay. Sanfdippo syndrome results in an excess of heparan sulfate and can be caused by a variety of enzyme deficiencies. 

A number of genetic diseases associated with proteoglycan metabolism, known as mucopolysaccharidoses, have been identified. Because proteoglycans are con-... 

Table 20-1 Lysosomal Storage Diseases Sphingolipidoses and Mucopolysaccharidoses... 

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