Information for Otolaryngologists

MPS I is a progressive, multi-systemic disease and patients typically see several specialists before getting a diagnosis. Recurrent ear infections, sleep apnea and other ear, nose, throat problems are common among patients with MPS I. Recognizing the signs and symptoms of the disease can help with early diagnosis.

Below are signs and symptoms that may lead to clinical suspicion of MPS I and warrant more definitive testing.

Chronic rhinitis

Chronic rhinitis and rhinorrhea without obvious infections are common features of MPS I. Typically, the bridge of the nose is flattened and the passage behind the nose may be smaller than usual because the bones in the mid-face have not grown well and the nose lining is thicker. GAG buildup in the soft tissues of the nose and throat, combined with abnormal bones, can cause the airway to become easily blocked. Severely affected individuals often have a chronic (long-term) discharge of thick mucus from the nose, and chronic ear and sinus infections.

Mildly affected individuals with attenuated disease may not be affected by ear, nose or chest problems.

Hearing loss

Moderate to severe hearing loss, which correlates with the severity of somatic disease, can occur in patients on the severe end of the disease spectrum. Hearing loss may be sensorineural or conductive, but is typically mixed.[6] Hearing impairment is most common in the high frequency range and thus can lead to significant difficulties in social interaction.

Mildly affected individuals with attenuated disease may not be affected by ear problems.

Otitis Media

What is otitis media? Otitis media (OM) is an infection or inflammation of the middle ear. This inflammation often begins when infections that cause sore throats, colds, or other respiratory or breathing problems spread to the middle ear. In MPS I, OM is caused, in part, by the buildup of glycosaminoglycans (GAGs) in the middle ear, nose, mouth, and throat.

Acute Otitis Media

Acute OM occurs when fluid is present in the middle ear, along with signs or symptoms of ear infection such as bulging eardrum often with pain, ear tugging, fever, irritability, decreased appetite, vomiting, and diarrhea. OM with effusion occurs when fluid is present without signs of infection. Although rare, complications can include tympanic membrane perforation, acute mastoiditis, cholesteatoma, meningitis, and epidural abscess.[1]  Some degree of deafness is common for both severe and attenuated patients, and can be made worse by frequent ear infections.  Mildly affected individuals with attenuated MPS I may be unaffected by ear, nose, throat, and chest problems.

Recurrent Otitis Media

Recurrent otitis media, infection of the middle ear, is one of the more stubborn problems for children with severe MPS I and to a lesser extent, individuals with attenuated MPS I who have moderate-to-severe symptoms.[1]  Recurrent OM is caused, in part, by the buildup of GAGs in the middle ear, nose, mouth, and throat.


Loud, frequent snoring may indicate obstructive sleep apnea, a symptom of MPS I. GAG storage within the oro-pharynx and associated enlargement of the tongue, tonsils, and adenoids, along with a narrowed trachea, thickened vocal cords, and redundant tissue in the upper airway, may contribute to airway obstruction, causing the sleep apnea.[6],[7],[8]

Mildly affected individuals with attenuated disease may not be affected by airway obstruction.

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  1. National MPS Society. Available at: Accessed April 11th, 2017.
  2. Clarke, L.A. Clinical diagnosis of lysosomal storage diseases. In: Organelle Diseases: Clinical Features, Diagnosis, Pathogenesis and Management. Applegarth, D.A., Dimmick, J.E., and Hall, J.G. eds. London: Chapman and Hall Medical; 1997; 46.
  3. Wraith, J.E., and Alani S.M. Carpal tunnel syndrome in the mucopolysaccharidoses and related disorders. Arch Dis Child. 1990; 65:962-963.
  4. Haddad, F.S., Jones, D.H., Vellodi, A., Kane, N., and Pitt, M.C. (1997) Carpal tunnel syndrome in the mucopolysaccharidoses and the mucolipidoses. J Bone Joint Surg Br. 1997; 79:578.
  5. Van Heest, A.E., House J., Krivit, W., and Walker, K. Surgical treatment of carpal tunnel syndrome and trigger digits in children with mucopolysaccharide storage disorders. J Hand Surg Am. 1998; 23:239-241.
  6. Neufeld EF, Muenzer J. The Mucopolysaccharidoses. In: Valle D, Beaudet AL, Vogelstein B, Kinzler KW, Antonarakis SE, Ballabio A, Gibson K, Mitchell G. eds. The Online Metabolic and Molecular Bases of Inherited Disease New York, NY: McGraw-Hill; 2014.§ionid=62642135. Accessed April 11, 2017.
  7. Myer, C.M.D. Airway obstruction in Hurler's syndrome - Radiographic features. Int J Pediatr Otorhinolaryngol. 1990;22:92-95.
  8. Peters, M.E., Arya, S., Langer, L.O., Gilbert, E.F., Carlson, R., and Adkins, W. Narrow trachea in mucopolysaccharidoses. Pediatr Radiol. 1985; 15:226-227.
  9. Stone DL, Sidransky E. Hydrops fetalis: lysosomal storage disorders in extremis. Adv Pediatric. 1999;46:409-440.