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Mucopolysaccharidoses
Nur Amalina bt Aminuddin Baki082012100067082012100063082012100071082012100075
Objective• To understand what is
mucopolysaccharidoses• T0 be able to list the features of
mucopolysaccharidoses• To know the types of
mucopolysaccharidoses and their causes with their diagnosis
Introduction • GAG = long chains of sugar
carbohydrates in cells that help build bone ,cartilage, tendons , corneas, skin and connective tissue
• GAG is made up of chains amino sugar + uronic acid
• Deficiency of enzyme to breakdown GAG
• so excessive accumulation of GAG(glycosaminoglycan) in lysosomes of various tissues
• Will result in lysis of lysosome release of all hydrolytic enzyme tissue destruction
Mucopolysaccharidoses
• All are inborn errors of metabolism • All these diseases are inherited
(autosomal recessive traits) except Hunter’s disease (X-linked
• Clinically Progressive disorders
Groups of GAG:
• Hyaluronic acid • Chondroitin sulphate• Dermatan sulphate• Heparan sulphate • Keratan sulphate• Heparin
Features • Coarse facial features( flat nasal bridge,
thick lips, and enlarged mouth and tongue)• Thick skin• Corneal opacity• Mental retardation• Gargoyle appearance• Short stature• Claw like fingers
Diagnosis• Urine test• Enzyme assays• Prenatal diagnosis• Genetic counselling
Treatment• No cure • Medical care is given to improve
quality of life– Physiotherapy– exercise– changes in diet
Type 1( Hurler’s)• L- Iduronidase• Mental retardation+++• Skeletal deformity ++• Corneal opacity++• Dermatan Sulphate and Heparan
Sulphate in urine• 1:100,000
Type 2 ( Hunter’s)• Iduronate sulphatase• Mental retardation+• Skeletal deformity ++• No Corneal opacity• Deafness • Dermatan Sulphate and Heparan
Sulphate in urine• 1: 250,000
Type 3 ( Sanfilippo’s)• N – acetyl glucosaminidase and
heparan sulfatase• Mental retardation++• Skeletal deformity +• Corneal opacity+• Heparan Sulphate in urine• 3 types• 1:500,000
Type 4 ( Morquio’s)• Galactosamine sulfatase and b- D
galactosidase• Mental retardation+• Skeletal deformity +• Corneal opacity+• Epiphyseal dysplasia +• Keratan Sulphate and Chondroitin Sulphate in
urine• 2 types • 1 :75,000
Type 5 ( Scheie’s)• L- Iduronidase• No Mental retardation• Mild Skeletal changes• Corneal opacity++• Dermatan Sulphate in urine• 1: 100,000
Type 6 (Maroteaux- Lamy’s) • N- acetyl –b-D- Galactosamino-4-
Sulfatase• No Mental retardation• Skeletal deformity +++• Corneal opacity++• Dermatan Sulphate in urine• 1 :100,000
Type 7 ( Sly’s)• B- Gluronidase• Mental retardation+• Dermatan Sulphate and Heparan
Sulphate in urine• <1: 250,000
Conclusion • The accumulation of GAG and
defiency of enzyme can lead to severe clinical condition based on Their site of accumulationThe type of GAG that accumulate
• HHSMSMS
Reference • DM Vasudevan, Sreekumari S and
Kannan Vaidyanathan, Textbook of Biochemistry for Medical Students, 6th Edition.