National Organization for Rare Disorders, Inc.

It is possible that the main title of the report Sialidosis is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • Alpha-Neuraminidase Deficiency
  • Cherry Red Spot and Myoclonus Syndrome
  • Glycoprotein Neuraminidase, Deficiency of
  • Lipomucopolysaccharidosis Type I
  • ML I
  • Mucolipidosis I
  • Sialidase Deficiency

Disorder Subdivisions

  • Sialidosis Type I (Juvenile)
  • Sialidosis Type II (Infantile)

General Discussion

Sialidosis is a very rare inherited metabolic disorder characterized by a deficiency of the enzyme alpha-neuraminidase. This disorder belongs to a group of diseases known as lysosomal disorders. Lysosomes are particles bound in membranes within cells that break down certain fats and carbohydrates. The deficiency of alpha-neuraminidase that characterizes Sialidosis leads to the abnormal accumulation of certain complex carbohydrates (mucopolysaccharides) and certain fatty substances (mucolipids) in many tissues of the body. Previously known as Mucolipidosis I, Sialidosis belongs to a subgroup of lysosomal diseases known as Mucolipidoses.

The symptoms of Sialidosis Type I, which typically begin during the 2nd decade of life, may include sudden involuntary muscle contractions (myoclonus), the appearance of red spots (cherry-red macules) in the eyes, and/or other neurological findings. Sialidosis Type II may begin during infancy or later. It is characterized by the same visual characteristics as Sialidosis Type I, as well as other symptoms such as mildly coarse facial features, skeletal malformations, and/or mild mental retardation. Sialidosis is inherited as an autosomal recessive genetic trait.


CLIMB (Children Living with Inherited Metabolic Diseases)
Climb Building
176 Nantwich Road
Crewe, Intl CW2 6BG
United Kingdom
Tel: +44 870 7700 325
Fax: +44 870 7700 327

Vaincre Les Maladies Lysosomales
2 ter avenue de Fance
Massy, 91300
Tel: 01 69 75 40 30
Fax: 01 60 11 15 83

Arc (a national organization on mental retardation)
1010 Wayne Ave
Suite 650
Silver Spring, MD 20910
Tel: (301)565-3842
Fax: (301)565-3843
Tel: (800)433-5255
TDD: (817)277-0553

NIH/National Digestive Diseases Information Clearinghouse
2 Information Way
Bethesda, MD 20892-3570
Tel: (301)654-3810
Fax: (301)907-8906
Tel: (800)891-5389

Society for Mucopolysaccharide Diseases
MPS House
Repton Place
White Lion Road
Buckinghamshire, HP7 9LP.
United Kingdom
Tel: 004401494 434156
Fax: 004401494 434252

Canadian Society for Mucopolysaccharide and Related Diseases, Inc.
PO Box 64714
Ontario, Intl L3R OM9
Tel: 905-479-8701
Fax: 905-479-8701
Tel: 800-667-1846

International Advocate For Glycoprotein Storage Diseases (ISMRD)
20880 Canyon View Drive
Saratoga, CA 95070
Tel: (410)628-9991

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223

Hide & Seek Foundation for Lysosomal Disease Research
6475 East Pacific Coast Highway Suite 466
Long Beach, CA 90803
Tel: (877)621-1122
Fax: (866)215-8850

For a Complete Report

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc. ® (NORD). A copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see

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