Metabolic defect: alpha-N-acetylneuraminidase deficiency Other glycan degradation diseases: aspartylglucosaminuria | fucosidosis: type I, type II | mannosidosis | sialidosis: type I

Current page: Sialidosis - type II 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

One of five conditions that account for the majority of cases of progressive myoclonus epilepsies. Enzyme deficiency results in accumulation of sialyloligosaccharides and sialylglycopeptides, affecting lymphocytes, fibroblasts, bone marrow cells, Kupffer cells (liver), and Schwann cells.

Hepatosplenomegaly		Corneal opacity		Macular cherry-red spots

Neurodegenerative disorder characterized by myoclonic seizures, tonic-clonic seizures, progressive neurologic dysfunction (ataxia), and cherry-red macular spots. Distinguished from Type 1 by early onset of progressive visceral, skeletal, neurological involvement. Type II has three variants:

Congenital onset - Stillborn, or death at an early age. If born live, presents with hydrops fetalis and other complications.

Infantile onset - Presents at birth to 12 months, ranging from normal-to-minimal abnormalities to neonates with ascites and hydrops fetalis.

Juvenile onset - Onset at end of 1st decade of life, progressive disorder with mucopolysaccharidosis-like phenotypes. Death occurs in the 2nd decade of life.

Congenital onset:

Ascites

Organomegaly

Hepatomegaly, with or without splenomegaly

Inguinal hernia

Infantile onset:

Visceromegaly

Renal involvement

Congenital onset:

Facial edema

Juvenile onset:

Dysostosis multiplex

Congenital onset:

Pericardial effusion

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Congenital onset:

Corneal opacifications

Cherry-red macular spots

Juvenile onset:

Cherry-red macular spots

Decreased visual activity

Mental retardation (all variants)

Juvenile onset:

Myoclonus

Angiokeratomas (juvenile variant)

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

2. Thomas, George. “Disorders of Glycoprotein Degradation: -Mannosidosis, -Mannosidosis, Fucosidosis, and Sialidosis.” The Metabolic and Molecular Bases of Inherited Disease, 8th Edition Online. McGraw-Hill. http://genetics.accessmedicine.com/server-java/Arknoid/amed/mmbid/co_chapters/ch140/ch140_p01.html Accessed September 2004.