Diseases & Conditions


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Hunter Syndrome


Synonyms of Hunter Syndrome
  • MPS Disorder II
  • MPS II
  • Mucopolysaccharidosis Type II

Disorder Subdivisions

  • MPS IIA
  • MPS IIB


General Discussion
Hunter syndrome, also known as mucopolysaccharidosis II, is a rare inborn error of metabolism characterized by inadequate production of an enzyme known as iduronate sulfatase, which is needed to break down complex sugars produced in the body. Symptoms include growth delay, joint stiffness, and coarsening of facial features. In severe cases, patients experience respiratory and cardiac problems, enlargement of the liver and spleen, and neurological deficits. The disorder can lead to premature death in severe cases.

Hunter syndrome is one of a group of hereditary metabolic diseases known as the mucopolysaccharidoses (MPS), 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 Hunter syndrome, deficiency or improper functioning of lysosomal enzymes leads to an abnormal accumulation of certain complex carbohydrates in cells within various tissues, such as the skeleton, joints, brain, spinal cord, heart, spleen, or liver.

Initial symptoms and findings associated with Hunter syndrome usually become apparent in children from two to four years of age. Such abnormalities may include progressive growth delays, resulting in short stature; joint stiffness, with associated restriction of movements; and coarsening of facial features, including thickening of the lips, tongue, and nostrils. Affected children may also have an abnormally large head (macrocephaly), a short neck and broad chest, delayed tooth eruption, progressive hearing loss, and enlargement of the liver and spleen (hepatosplenomegaly). Two relatively distinct clinical forms of Hunter syndrome have been recognized. In the late-onset, mild form of the disease (MPS IIB), intelligence may be normal or only slightly impaired. However, in the early-onset, more severe form (MPS IIA), profound mental retardation may be apparent by late childhood. In addition, slower disease progression tends to occur in those with the mild form of the disorder.

Hunter syndrome is inherited as an X-linked recessive trait. Mild and severe forms of the disorder result from changes (mutations) of a gene (i.e., IDS gene) that regulates production of the iduronate sulfatase enzyme. The IDS gene is located on the long arm (q) of chromosome X (Xq28).

Organizations related to Hunter Syndrome
  • CLIMB (Children Living with Inherited Metabolic Diseases)
    Climb Building
    Crewe Intl CW2 6BG
    Phone #: +44- 87-0 7700 325
    800 #: --
    e-mail: info@climb.org.uk
    Home page: http://www.CLIMB.org.uk
  • Canadian Society for Mucopolysaccharide and Related Diseases, Inc.
    PO Box 64714
    Ontario Intl L3R OM9
    Phone #: 905--47-9-8701
    800 #: 800--66-7-1846
    e-mail: lori.mps@rogers.com
    Home page: http://www.mpssociety.ca
  • Hide & Seek Foundation for Lysosomal Disease Research
    4123 Lankershim Blvd.
    North Hollywood CA 91602-2828
    Phone #: 818-762-8621
    800 #: N/A
    e-mail: info@hideandseek.org
    Home page: http://www.hideandseek.org
  • Let Them Hear Foundation
    1900 University Ave #101
    East Palo Alto CA 94303
    Phone #: 650-462-3143
    800 #: 877-735-2929
    e-mail: info@letthemhear.org
    Home page: http://www.letthemhear.org
  • MUMS (Mothers United for Moral Support, Inc) National Parent-to-Parent Network
    150 Custer Court
    Green Bay WI 54301-1243
    Phone #: 920-336-5333
    800 #: 877-336-5333
    e-mail: mums@netnet.net
    Home page: http://www.netnet.net/mums/
  • Madisons Foundation
    PO Box 241956
    Los Angeles CA 90024
    Phone #: 310-264-0826
    800 #: N/A
    e-mail: getinfo@madisonsfoundation.org
    Home page: http://www.madisonsfoundation.org
  • March of Dimes Birth Defects Foundation
    1275 Mamaroneck Avenue
    White Plains NY 10605
    Phone #: 914-428-7100
    800 #: 888-663-4637
    e-mail: Askus@marchofdimes.com
    Home page: http://www.marchofdimes.com
  • NIH/National Institute of Diabetes, Digestive & Kidney Diseases
    Endocrine Diseases Metabolic Diseases Branch
    Bethesda MD 20892-3570
    Phone #: 301-654-3810
    800 #: --
    e-mail: NDDIC@info.niddk.nih.gov
    Home page: http://www.niddk.nih.gov
  • National MPS (Mucopolysaccharidoses/Mucolipidoses) Society, Inc.
    PO Box 14686
    Durham NC 27709-4686
    Phone #: 919-806-0101
    800 #: --
    e-mail: info@mpssociety.org
    Home page: http://www.mpssociety.org
  • Society for Mucopolysaccharide Diseases
    46 Woodside Road
    Buckinghamshire None HP6 6AJ
    Phone #: 004-401-494 434156
    800 #: --
    e-mail: mps@mpssociety.co.uk
    Home page: http://www.mpssociety.co.uk
  • The Arc (a national organization on mental retardation)
    1010 Wayne Ave
    Silver Spring MD 20910
    Phone #: 301-565-3842
    800 #: 800-433-5255
    e-mail: info@thearc.org
    Home page: http://www.thearc.org/
  • Vaincre Les Maladies Lysosomales
    2 ter avenue de Fance
    Massy None 91300
    Phone #: 01 -69 -75 40 30
    800 #: --
    e-mail: accueil@vml-asso.org
    Home page: http://www.vml-asso.org



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 http://www.rarediseases.org/search/rdblist.html