What is hunter

This website is intended for healthcare professionals outside of the US and UK

Hunter syndrome (or Mucopolysaccharidosis II, MPS II), is a rare X-linked, recessive lysosomal storage disorder that primarily affects males (~1 in 162,000 live births).1,2

Individuals with Hunter syndrome have a mutation in the IDS gene resulting in a deficiency of the iduronate-2-sulfatase (I2S) enzyme, which is involved in the degradation of glycosaminoglycans (GAGs). Therefore, undegraded or partially degraded GAGs accumulate in almost all cells and tissues in the body, affecting organ function.1

Presentation of Hunter syndrome

Hunter syndrome is a chronic, multisystemic, progressive metabolic disease.3 A wide variety of multisystemic signs and symptoms are linked to Hunter syndrome; click here for more information. Both the age of onset and progression of symptoms of this multisystemic disease are heterogeneous, which can often lead to a delay between disease presentation and diagnosis.1 MPS II presents across a spectrum of clinical severity, where attenuated cases have non-neuronopathic disease presenting with somatic symptoms only, and severe cases have neuronopathic disease involving the central nervous system (CNS), in addition to somatic symptoms.3–5 At present, genotype-phenotype correlation is not possible, except that IDS gene mutations (e.g. complete deletion/rearrangement) that result in a complete absence of I2S activity are reported to lead to a severe disease phenotype.3,6 Patient phenotypes are categorised based on neurological involvement, age of symptom onset, and life expectancy.4,5

Life expectancy in Hunter syndrome

The clinical manifestations of Hunter syndrome lead to decreased life expectancy.7,8 Historically, without treatment, death often occurred in the second decade of life, although patients with a non-neuronopathic form of the disease may survive into adulthood.7,8 The main causes of death in patients with Hunter syndrome, regardless of the phenotype, are respiratory and/or cardiac disease.5,9

Management of Hunter syndrome

While a large part of Hunter syndrome patient management focuses on treating symptoms, disease-specific treatment, in the form of I2S enzyme replacement therapy (ERT), is recommended by clinical guidelines as the standard of care for patients with Hunter syndrome to be initiated as early as possible after diagnosis.1,10 Following the approval of recombinant human I2S in the United States (2006) and Europe (2007), ELAPRASE® has now been available for over 15 years for the long-term treatment of Hunter syndrome.7,8,11


This disease-awareness website, sponsored by Takeda, is an educational resource for healthcare professionals to discover more about Hunter syndrome. The website provides detailed information in the form of infographics, videos, and case studies. To find out more about how to recognise and manage Hunter syndrome visit huntersyndrome.info.


  1. Scarpa M, Almassy Z, Beck M et al. Orphanet J Rare Dis. 2011;6:72.

  2. Meikle P, Hopwood J, Clague, A et al. JAMA. 1999;281(3):249-254.

  3. Martin R, Beck M, Eng C et al. Pediatrics. 2008:129(2) e377-386.

  4. Muenzer J, Beck M, Giugliani R et al. Genet Med. 2011;13(2) 102-109.

  5. Young LD & Harper PS. Arch Dis Child. 1982;57(6)867-874.

  6. Wraith JE, Scarpa M, Beck M et al. Eur J Pediatr. 2008:167(3)267-277.

  7. Muenzer J, Giugliani R, Scarpa M et al. Orphanet J Rare Dis. 2017;12:82.

  8. Muenzer J, Bodamer O, Burton B et al. Eur J Pediatr. 2012; 171:181-188.

  9. Burton B, Jego V, Mikl J et al. J Inherit Metab Dis. 2017;40(6)867-874.

  10. Giugliani R, Villarreal M, Valdez C. et al. Genet Mol Biol. 2014;37(2):315–329.