Mucopolysaccharidosis Type II

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Mucopolysaccharidosis Type II is not the name you expected.

Disorder Subdivisions

  • None

General Discussion

Mucopolysaccharidosis type II (MPS II) is a rare inborn error of metabolism that affects every organ of the body. Although the age of onset, disease severity and the rate of progression of the disease vary significantly, initial symptoms and findings associated with MPS II usually become apparent in children from two to four years of age. Manifestations of MPS II may include joint stiffness, with associated restriction of movements; and coarsening of facial features, including thickening of the lips, tongue (macroglossia), and nostrils. Affected children may also have an abnormally large head (macrocephaly), a short neck and broad chest, delayed tooth eruption, progressive hearing loss, enlargement of the liver and spleen (hepatosplenomegaly), and progressive growth delays resulting in short stature. Two relatively distinct clinical forms of MPS II have been recognized. In the non-neuronopathic form (formerly defined as slowly progressive milder form) of the disease, intelligence may be normal or only slightly impaired. In the neuronopathic for of the disease (formerly called early progressive more severe form), intellectual disabilities may be apparent in the early life of the patient.

MPS II is an X-linked genetic condition that mostly affects males; although a few females have been described as well, and is caused by changes (mutations) of the IDS gene that regulates the production of the iduronate 2-sulfatase enzyme. This enzyme is needed to break-down complex sugars produced in the body.

MPS II is one of a group of hereditary metabolic diseases known as the mucopolysaccharidoses which in turn, are part of a group known as lysosomal storage disorders. Lysosomes function as the primary digestive units within cells. Enzymes within lysosomes break down or digest particular nutrients, such as certain carbohydrates and fats. In individuals with MPS disorders, including MPS II, deficiency or improper functioning of lysosomal enzymes leads to an abnormal accumulation of certain complex carbohydrates in cells (mucopolysaccharides, also known as glycosaminoglycans) within various tissues, such as the skeleton, joints, brain, spinal cord, heart, spleen, or liver.

Supporting Organizations

CLIMB (Children Living with Inherited Metabolic Diseases)

Climb Building
176 Nantwich Road
Crewe, CW2 6BG
United Kingdom
Tel: 4408452412173
Fax: 4408452412174

Canadian Society for Mucopolysaccharide and Related Diseases, Inc.

#218-2055 Commercial Drive
Vancouver, BC V5N 0C7
Tel: (604) 924-5130
Tel: 1-800-667-1846

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

Let Them Hear Foundation

1900 University Avenue, Suite 101
East Palo Alto, CA 94303
Tel: (650)462-3174
Fax: (650)462-3144

NIH/National Institute of Diabetes, Digestive & Kidney Diseases

Office of Communications & Public Liaison
Bldg 31, Rm 9A06
Bethesda, MD 20892-2560
Tel: (301)496-3583

National MPS Society, Inc.

PO Box 14686
Durham, NC 27709
Tel: (919)806-0101
Fax: (919)806-2055
Tel: (877)677-1001

Proyecto Pide un Deseo México, i.a.p.

Altadena #59-501
Benito Juárez, 03810
México, D.F.
Tel: +52 55 5543-2447
Fax: 55-5543-5450

Society for Mucopolysaccharide Diseases

MPS House
Repton Place
Buckinghamshire, HP7 9LP
United Kingdom
Tel: 03453899901
Fax: 03453899902

Xtraordinary Joy

2603 NW 13th St. #327
Gainesville, FL 32609

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report.

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated:  6/28/2016
Copyright  2016 National Organization for Rare Disorders, Inc.