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Disease Profile

Mucopolysaccharidosis type III

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.
1-9 / 1 000 000

331 - 2,979

US Estimated

1-9 / 1 000 000

514 - 4,622

Europe Estimated

Age of onset

Childhood

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ICD-10

E76.2

Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

Mucopoly-saccharidosis type 3; Sanfilippo syndrome; MPSIII;

Categories

Congenital and Genetic Diseases; Eye diseases; Metabolic disorders;

Summary

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

Symptoms

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.

Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Central nervous system degeneration
0007009
Chronic otitis media
Chronic infections of the middle ear
0000389
Coarse hair
Coarse hair texture
0002208
Delayed speech and language development
Deficiency of speech development
Delayed language development
Delayed speech
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language delay
Language delayed
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
Speech delay

[ more ]

0000750
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
Progressive neurologic deterioration
Worsening neurological symptoms
0002344
30%-79% of people have these symptoms
Abnormal clavicle morphology
Abnormal collarbone
0000889
Abnormal form of the vertebral bodies
0003312
Abnormality of the ribs
Rib abnormalities
0000772
Adenoiditis
0031458
Ataxia
0001251
Brain imaging abnormality
0410263
Cataract
Clouding of the lens of the eye
Cloudy lens

[ more ]

0000518
Coarse facial features
Coarse facial appearance
0000280
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
Heparan sulfate excretion in urine
0002159
Hepatomegaly
Enlarged liver
0002240
Hyperactivity
More active than typical
0000752
Intermittent diarrhea
0002254
Myopia
Close sighted
Near sighted
Near sightedness
Nearsightedness

[ more ]

0000545
Recurrent sinopulmonary infections
Recurrent sinus and lung infections
0005425
Specific learning disability
0001328
Splenomegaly
Increased spleen size
0001744
Synophrys
Monobrow
Unibrow

[ more ]

0000664
Thick hair
Increased hair density
0100874
Tonsillitis
Inflammation of tonsils
0011110
Vocal cord paresis
Weakness of the vocal cords
0001604
5%-29% of people have these symptoms
Abnormal aortic valve morphology
0001646
Abnormal mitral valve morphology
0001633
Abnormal myocardium morphology
0001637
Abnormal pyramidal sign
0007256
Abnormal temper tantrums
0025160
Abnormality of the dentition
Abnormal dentition
Abnormal teeth
Dental abnormality

[ more ]

0000164
Abnormality of the middle ear ossicles
0004452
Aggressive behavior
Aggression
Aggressive behaviour
Aggressiveness

[ more ]

0000718
Aspiration pneumonia
0011951
Atrioventricular block
Interruption of electrical communication between upper and lower chambers of heart
0001678
Avascular necrosis of the capital femoral epiphysis
0005743
Cardiomegaly
Enlarged heart
Increased heart size

[ more ]

0001640
Constipation
0002019
Constrictive median neuropathy
0012185
Dementia
Dementia, progressive
Progressive dementia

[ more ]

0000726
Dolichocephaly
Long, narrow head
Tall and narrow skull

[ more ]

0000268
Dysarthria
Difficulty articulating speech
0001260
Dysostosis multiplex
0000943
Dysphagia
Poor swallowing
Swallowing difficulties
Swallowing difficulty

[ more ]

0002015
Fatigable weakness of swallowing muscles
0030195
Flexion contracture
Flexed joint that cannot be straightened
0001371
Hip dysplasia
0001385
Hip pain
0030838
Hydrocephalus
Too much cerebrospinal fluid in the brain
0000238
Hyperactive deep tendon reflexes
0006801
Increased susceptibility to fractures
Abnormal susceptibility to fractures
Bone fragility
Frequent broken bones
Increased bone fragility
Increased tendency to fractures

[ more ]

0002659
Inguinal hernia
0000023

Diagnosis

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.

    Treatment

    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.

      Organizations

      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).

          Learn more

          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.

              References

              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; https://www.nlm.nih.gov/medlineplus/ency/article/001210.htm. Accessed 7/2/2015.

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