National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Mucopolysaccharidosis type III


Other Names:
Mucopoly-saccharidosis type 3; Sanfilippo syndrome; MPSIII; Mucopoly-saccharidosis type 3; Sanfilippo syndrome; MPSIII; Mucopolysaccharidosis type 3; Sanfilippo disease See More
Categories:
Subtypes:
This disease is grouped under:
Mucopolysaccharidosis type III (MPS III) is a genetic disorder that makes the body unable to break down large sugar molecules called glycosaminoglycans (GAGs, formerly called mucopolysaccharides).[1][2] Specifically, people with this condition are unable to break down a GAG called heparan sulfate.[2] Affected individuals can have severe neurological symptoms, including progressive dementia, aggressive behavior, hyperactivity, seizures, deafness, loss of vision, and an inability to sleep for more than a few hours at a time.[1] MPS III is inherited in an autosomal recessive manner.[2] There is no specific treatment for this condition.[2] Most people with MPS III live into their teenage years, and some live longer.[1] 

MPS III is divided into four subtypes, known as A, B, C and D.[1][2] Each subtype is caused by the alteration of a different enzyme needed to completely break down heparan sulfate. The different types of MPS III have similar signs and symptoms, although type A is the most severe.[1][2]

To view the GARD pages on the subtypes of MPS III, click on the following links:

Mucopolysaccharidosis type IIIA
Mucopolysaccharidosis type IIIB
Mucopolysaccharidosis type IIIC
Mucopolysaccharidosis type IIID

Last updated: 7/7/2011

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Chronic otitis media
Chronic infections of the middle ear
0000389
Coarse hair
Coarse hair texture
0002208
Generalized hirsutism
Excessive hairiness over body
0002230
Intellectual disability, progressive
Mental retardation, progressive
Progressive mental retardation
[ more ] 		0006887
Intellectual disability, severe
Early and severe mental retardation
Mental retardation, severe
Severe mental retardation
[ more ] 		0010864
Malabsorption
Intestinal malabsorption
0002024
Mucopolysacchariduria 0008155
Sleep disturbance
Difficulty sleeping
Trouble sleeping
[ more ] 		0002360
30%-79% of people have these symptoms
Abnormal form of the vertebral bodies 0003312
Abnormality of the clavicle
Abnormal collarbone
0000889
Abnormality of the ribs
Rib abnormalities
0000772
Ataxia 0001251
Cataract
Clouding of the lens of the eye
Cloudy lens
[ more ] 		0000518
Corneal opacity 0007957
Craniofacial hyperostosis
Excessive bone growth of the skull and face
0004493
Developmental regression
Loss of developmental milestones
Mental deterioration in childhood
[ more ] 		0002376
Genu valgum
Knock knees
0002857
Hearing impairment
Deafness
Hearing defect
[ more ] 		0000365
Hip dysplasia 0001385
Hypertonia 0001276
Inguinal hernia 0000023
Joint stiffness
Stiff joint
Stiff joints
[ more ] 		0001387
Myopia
Close sighted
Near sighted
Near sightedness
Nearsightedness
[ more ] 		0000545
Scoliosis 0002650
Seizure 0001250
Umbilical hernia 0001537
Vocal cord paresis
Weakness of the vocal cords
0001604
5%-29% of people have these symptoms
Hepatomegaly
Enlarged liver
0002240
Splenomegaly
Increased spleen size
0001744
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Last updated: 7/1/2020

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. 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.
  • Orphanet lists international laboratories offering diagnostic testing for this condition.

The resources below provide information about treatment options for this condition. If you have questions about which treatment is right for you, talk to your healthcare professional.

Management Guidelines

  • Project OrphanAnesthesia is a project whose aim is to create peer-reviewed, readily accessible guidelines for patients with rare diseases and for the anesthesiologists caring for them. The project is a collaborative effort of the German Society of Anesthesiology and Intensive Care, Orphanet, the European Society of Pediatric Anesthesia, anesthetists and rare disease experts with the aim to contribute to patient safety.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Mucopolysaccharidosis type III. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.
  • Orphanet lists European clinical trials, research studies, and patient registries enrolling people with this condition. 

Patient Registry

  • The Lysosomal Disease Network is a team of doctors, nurses, research coordinators, and research labs throughout the U.S., working together to improve the lives of people with this condition through research. The Lysosomal Disease Network has a registry for patients who wish to be contacted about clinical research opportunities.

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Social Networking Websites

  • RareConnect has an online community for patients and families with this condition so they can connect with others and share their experiences living with a rare disease. The project is a joint collaboration between EURORDIS (European Rare Disease Organisation) and NORD (National Organization for Rare Disorders).

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Financial Resources

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • The Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Mucopolysaccharidosis type III. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. Mucopolysaccharidoses Fact Sheet. National Institute of Neurological Disorders and Stroke (NINDS). February 23, 2016; https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Mucopolysaccharidoses-Fact-Sheet.
  2. Haldeman-Englert C. Sanfilippo syndrome. MedlinePlus. May 7, 2013; http://www.nlm.nih.gov/medlineplus/ency/article/001210.htm. Accessed 7/2/2015.