Mucopolysaccharidosis type II

Is carrier testing for mucopolysaccharidosis II (MPS II) available?

Yes, carrier testing for MPS II is available. Testing usually begins with an affected male relative, if one is available for testing, to determine the disease-causing mutation. If there is not living affected male relative, testing possible female carriers involves a type of genetic testing called sequence analysis. This test requires a small blood sample and reads through the genetic code of the IDS gene looking for errors. If a mutation is not found using sequence analysis, then two other tests can be performed to look for mutations that cause MPS II. Genetic testing detects most of the mutations that cause MPS II, but may not detect all mutations that cause this condition Therefore, testing cannot definitively determine that a person is not a carrier for MPS II.

The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. Click here to link directly to a list of labs conducting carrier screening for MPS II. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.


Last updated on 05-01-20

How is mucopolysaccharidosis II (MPS II) inherited?

MPS II is inherited in an X-linked recessive pattern, which means that this conditions occurs almost exclusively in males. Females are generally unaffected carriers of this condition. In a family with more than one affected individual, the mother of the affected males must be a carrier. When a carrier female has a child, there is a 25% (1 in 4) chance that she will have a affected son.

Last updated on 05-01-20

What is mucopolysaccharidosis II (MPS II)?

Mucopolysaccharidosis II (MPS II) is an inherited disorder of carbohydrate metabolism that occurs almost exclusively in males. It is characterized by distinctive facial features, a large head, hydrocephalus, enlargement of the liver and spleen (hepatosplenomegaly), umbilical or inguinal hernia, and hearing loss. Individuals with this condition may additionally have joint deformities and heart abnormalities involving the valves. MPS II is caused by mutations in the IDS gene and is inherited in an X-linked manner.

There is a wide range in severity of symptoms present in individuals with MPS II. Previously, MPS II was classified as severe and attenuated based on severity. More recently, the terms slowly progressive and early progressive have been suggested. While both types affect many different parts of the body, people with the severe type also experience a decline in intellectual function and a more rapid disease progression. The life expectancy for people with the severe type is 10 to 20 years. Individuals with the less severe type typically live into adulthood and intelligence is not affected. Treatment is focused on managing the signs and symptoms present in each individual.

Last updated on 05-01-20

Who can I contact to learn more about genetic testing for mucopolysaccharidosis II (MPS II)?

We recommend that you contact a genetics clinic to learn more about carrier testing for MPS II. To find a genetics clinic near you, we recommend contacting your primary doctor for a referral.

The following online resources can also help you find a genetics professional in your community:

  • GeneTests offers a searchable directory of U.S. and international genetics and prenatal diagnosis clinics.
  • The National Society of Genetic Counselors provides a database of genetics counseling services, searchable by location, name, institution, type of practice, or specialty.
  • The University of Kansas Medical Center provides a list of links to genetic centers and clinics, associations, and university genetics departments.
  • The American College of Medical Genetics has a Genetics Clinics Database for individuals who wish to locate a U.S. genetics center.
  • The American Society of Human Genetics (ASHG) is a professional organization of researchers and clinical geneticists. The ASHG maintains a database of its members, some of whom live outside of the United States. Visit the ASHG site if you are interested in obtaining a list of the geneticists in your country, though some may be researchers only and may not offer medical care.

You can also contact the MPS Society for more information on this condition and genetic testing.

National Mucopolysaccharidoses/Mucolipidoses Society (MPS), Inc
National MPS Society
4220 NC Hwy 55, Ste.140
Durham, NC 27713
Toll-free: 877-MPS-1001
Phone: 919-806-0101
Fax: 919-806-2055
Web site:

Last updated on 05-01-20

Name: Canadian Society for Mucopolysaccharide and Related Diseases Inc. (Canadian MPS Society) #218-2055 Commercial Drive Vancouver, BC V5N OC7
Phone: 604-924-5130 Toll Free: 800-667-1846 Fax : 604-924-5131 Email: Url:
Name: National MPS Society P.O. Box 14686
Durham, NC, 27709-4686, United States
Phone: +1-919-806-0101 Toll Free: 1-877-MPS-1001 (1-877-677-1001) Fax : +1-919-806-2055 Email: Url:
Name: Society for Mucopolysaccharide (MPS) Diseases MPS House Repton Place White Lion Road Amersham Buckinghamshire
United Kingdom
Phone: (+44) 0345 389 9901 Email: Url:

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