Hunter syndrome (MPS II) can predispose pediatric patients to repeat respiratory and ear infections, which, often present before Hunter syndrome is diagnosed.1,2,3 Alongside these recurrent infections, other Hunter syndrome symptoms, including chronic rhinorrhoea, nasal obstruction, noisy breathing, hearing loss and enlarged adenoids and tonsils, in addition to a distended abdomen (hepatosplenomegaly) and chronic diarrhoea, may all contribute to Hunter syndrome, being mistaken to have an infectious/immune-related cause.4,5,6 Therefore, an undiagnosed Hunter syndrome patient may be referred to an immunologist or allergist to manage the recurrent infections and pulmonary symptoms.1,2,3 Click here to learn more about the signs and symptoms of Hunter syndrome.

The American Academy of Allergy, Asthma & Immunology (AAAAI) and the American College of Allergy, Asthma & Immunology (ACAAI) practice parameter for the diagnosis of primary immunodeficiency disorders note the need to exclude the possibility of anatomical or biochemical causes of infection susceptibility, before focusing on investigating immunodeficiency.7 Click here to download a poster highlighting the key exclusion step in the AAAAI/ACAAI practice parameters.

Biochemical and anatomical changes to airways are an underlying cause of recurrent respiratory infections in Hunter syndrome.1,8 Hunter syndrome patients may have enlarged tonsils, adenoids, gums and tongue, and tracheomalacia, and thick secretion, including chronic rhinorhoea.4,8

Click here to read more about the insidious anatomical and biochemical changes that occur in Hunter syndrome, predisposing patients to respiratory infections

Recognising the presence of biochemical and anatomical features of Hunter syndrome that predispose patients to recurrent infections may indicate the need to look for diagnosis outside of immunodeficiency,7 but the key to narrowing in on Hunter syndrome is recognising concurrent multisystemic symptoms, alongside the recurrent infections, such as:5

  • Hernia – inguinal and umbilical hernias are frequent and often require repair3,6
  • Organomegaly – enlarged liver and spleen are common4,6
  • Developmental delays – some patients have a cognitive impairment, first presenting as a delay in development seen by 1.5-2 years of age9
  • Coarse facial features – dysmorphic facial features are a strong diagnostic feature of Hunter syndrome; however, they may be subtle in some patients4,5
  • Skeletal dysplasia and joint stiffness – chronic joint stiffness and skeletal dysplasia are among the common early signs of Hunter syndrome, with patients experiencing restricted mobility from a young age4,6,10
  • Cardiac involvement – some Hunter syndrome patients may have a heart murmur early in the disease course5. Although heart murmur is often benign, cardiac valve disease is common among patients11


Learn more about how Hunter syndrome is diagnosed
Download an informative eBook about Hunter syndrome for Immunologists

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