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Start free with EleplanMucopolysaccharidosis type 2
ORPHA:580Disease
Also called Hunter syndrome · Iduronate 2-sulfatase deficiency · MPS2 · MPSII · Mucopolysaccharidosis type II
What it is
A lysosomal storage disease with multisystemic involvement leading to a massive accumulation of glycosaminoglycans and a wide variety of symptoms including distinctive coarse facial features, short stature, cardio-respiratory involvement and skeletal abnormalities. It manifests as a continuum varying from a severe form with neurodegeneration to an attenuated form without neuronal involvement.
Key facts
- Prevalence
- 1-9 / 1 000 000 (Europe)
- Age of onset
- Childhood
- Inheritance
- X-linked recessive
- Classified as
- Disease
Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.
Signs and symptoms
Very common80–99%
5Common30–79%
36- Abnormal heart valve morphology
- Atypical behavior
- Chronic diarrhea
- Cognitive impairment
- Conductive hearing impairment
- Contractures of the large joints
- Decreased nerve conduction velocity
- Dermatan sulfate excretion in urine
- Developmental regression
- Dysostosis multiplex
- Enlarged tonsils
- Flexion contracture of digit
- Full cheeks
- Gingival overgrowth
- Growth delay
- Heparan sulfate excretion in urine
- Hepatomegaly
- Hoarse voice
- Inguinal hernia
- Irregularity of vertebral bodies
- Macroglossia
- Mental deterioration
- Mongolian blue spot
- Peripheral visual field loss
- Progressive neurologic deterioration
- Recurrent ear infections
- Recurrent upper respiratory tract infections
- Retinal degeneration
- Retinopathy
- Sensorineural hearing impairment
- Sleep abnormality
- Sleep apnea
- Sleep-wake cycle disturbance
- Splenomegaly
- Thick vermilion border
- Umbilical hernia
Sometimes5–29%
26- Abnormal aortic morphology
- Abnormal epiphyseal ossification
- Abnormal full-field electroretinogram
- Abnormality of retinal pigmentation
- Abnormal mitral valve morphology
- Abnormal nasal mucus secretion
- Abnormal pulmonary valve morphology
- Abnormal tricuspid valve morphology
and 18 more in this range
These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.
Genes reported in subtypes
Orphanet records this gene on 2 more specific entries under this disorder, not on this entry itself:
A well-studied disease is usually split into subtypes, and the gene is curated on whichever one the evidence belongs to. Open a subtype to see which gene goes with it.
ICD-10 codes
ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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