A rare combination of symptoms should make you think twice.

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Information for specialists
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Specialist information

Diagnosing Hunter syndrome (MPS II)

Hunter syndrome is characterized by a deficiency in the activity of the lysosomal enzyme iduronate-2-sulfatase (I2S), which is one of the lysosomal enzymes responsible for degrading glycosaminoglycans (GAGs).1

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James was diagnosed with Hunter syndrome before the age of 4 years.1 He presented with multiple signs and symptoms prior to diagnosis, many of which were initially overlooked as common childhood complaints.2

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0–6 months

0–6 months
  • Colds & ear infections
  • Inguinal hernia

6–12 months

6–12 months
  • Repeated infections
  • Distended abdomen

12–18 months

12–18 months
  • T-tubes
  • Adenoidectomy / adenotonsillectomy

What is Hunter syndrome (MPS II)?

Hunter syndrome, also known as Mucopolysaccharidosis type II (MPS II), is one of a group of rare disorders known as the mucopolysaccharidoses.3

It is a rare, X-linked genetic disorder almost exclusively affecting males, with an incidence of 1 in 162,000 live male births.4,5

Hunter syndrome causes a deficiency or absence of a lysosomal enzyme, which interferes with the body’s ability to break down glycosaminoglycans (GAGs). This leads to the accumulation of GAGs, which causes organ damage.6-8

Patients usually appear normal at birth. Depending on the severity of the disease manifestation, initial signs and symptoms present between the ages of 18 months and 4 years and life expectancy varies from <20 years to 50–60 years.4

Knowing which symptoms to look out for is critical for early diagnosis.2

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Related video
Awareness & diagnosis of Hunter syndrome (MPS II)

Professor Barbara Burton explores why this condition can be difficult to recognize and discusses the importance of identifying MPS II as early as possible.

Importance of early identification

Signs & symptoms

Increase your knowledge by exploring the signs & symptoms that should trigger suspicion of Hunter syndrome (MPS II).


Age of onset

Patients usually appear normal at birth. Although signs and symptoms may appear earlier in some patients, they commonly present between the ages of 18 months and 4 years.


Testing & diagnosis

Learn about the diagnostic algorithm for Hunter syndrome (MPS II).


References:  1. Mendelsohn NJ et al. Genet Med 2010; 12(12): 816–822.  2. Burton BK, Giugliani R. Eur J Pediatr 2012; 171(4): 631–639.  3. Muenzer J. Rheumatology (Oxford) 2011; 50 Suppl 5: v4–12.  4. Scarpa M, et al. Orphanet J Rare Dis 2011; 6: 72.  5. Meikle PJ et al. JAMA 1999; 281(3):249-254.  6. Wraith JE et al. Genet Med 2008; 10(7): 508–16.  7. Muenzer J et al. Mol Genet Metab 2007; 90(3):329-337.  8. Neufeld EF, Muenzer J. In: Scriver CR et al (Eds). The Metabolic and Molecular Basis of Inherited Disease. New York, NY: McGraw-Hill; 2001: 3421-3452.

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