Metabolic defect: Type A - galactose 6-sulfatase deficiency; Type B - beta-galactosidase deficiency Other glycosaminoglycans metabolism diseases (mucopolysaccharidoses): MPS I | MPS II | MPS III | MPS VI | MPS VII

Current page: MPS IV Select Another Disease Select disease Acid sphingomyel. def. Aspartylglycosaminuria Cystinosis Fabry disease Farber disease Fucosidosis type I Fucosidosis type II Galactosialidosis Gaucher type I Gaucher type II Gaucher type III GM1 gangliosidosis I GM1 gangliosidosis II GM1 gangliosidosis III Infantile sialic acid Krabbé disease Mannosidosis Metachr. leukodys. I Metachr. leukodys. II Metachr. leukodys. III MPS I MPS II Hunter MPS III Sanfilippo MPS IV Morquio MPS VI Maroteaux-Lamy MPS VII Sly Mucolipidosis II Mucolipidosis III Mucolipidosis IV Neuro ceroid lipof I Neuro ceroid lipof II Neuro ceroid lipof III Neuro ceroid lipof IV Pompe disease Pycnodysostosis Salla disease Sandhoff type I Sialidosis type I Sialidosis type II Tay-Sachs type I Tay-Sachs type II Tay-Sachs type III

Enzyme deficiency results in progressive accumulation of the glycosaminoglycans (gags) keratan sulfate and chondroitin 6-sulfate in type A, and keratan sulfate in type B.

Skeletal abnormality - hand		Skeletal abnormality - flattened vertebrae		Corneal clouding

Image Credits: Skeletal abnormality courtesy of Atlas of Metabolic Diseases, Arnold, 1998. Corneal clouding courtesy of Desnick et al., 2003, with permission from author and publisher.

Progressive disorder with multiple organ and tissue involvement. Wide spectrum of involvement between the two types. Onset is variable but usually obvious between 1 and 3 years of age. Short-trunk dwarfism; progressive and severe skeletal dysplasia with subsequent effects on the central nervous system. Survival beyond the 3rd decade not common in more severe cases.

Genu valgum

Kyphosis

Growth retardation with short trunk and neck

Waddling gait with a tendency to fall

Platyspondylia

Odontoid hypoplasia

Hyperlordosis

Scoliosis

Ovoid deformities of the vertebrae

Ulnar deviation of the wrist

Valgus deformity of the elbow

Inclinations of distal ends of radius and ulna toward each other

Deformities of metacarpals and short phalanges

Epiphyseal deformities of the tubular bones

Widened metaphyses

Osteoporosis

Hypermobile joints secondary to ligamentous laxity

Cervical myelopathy

Unusual facial features (coarse facies, prognathism, broad mouth)

Small teeth with thin enamel

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Restrictive chest wall movement

Cardiac valvular lesions

Hearing impairment

Mild corneal clouding

Upper airway obstruction

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1. Neufeld EF, Muenzer J. The mucopolysaccharidoses. In: The Metabolic Bases of Inherited Disease. New York: mcgraw Hill, 2001; 3421-3452.

2. Clarke LA. Clinical diagnosis of lysosomal storage diseases. In: Applegarth DA, Dimmick JE, JG Hall. Organelle Diseases: Clinical Features, Diagnosis, Pathogenesis and Management. London: Chapman and Hall 1997; 37-71.

3. Meikle PJ, Hopwood JJ, Clague AE, Carey WF. Prevalence of Lysosomal Storage Disorders. JAMA. 1999; 281: 249-254.