Information for General or Pediatric Surgeons

MPS I is a progressive, multi-systemic disease and presenting symptoms can vary depending on disease severity. Because MPS I can affect many different organ systems, patients typically see several specialists before getting a diagnosis. Below are presenting symptoms encountered by general and pediatric surgeons that may lead to clinical suspicion of MPS I and warrant more definitive testing.

Abnormal gait

The feet of patients with severe forms of MPS I are broad and may be stiff with the toes curled under, rather like the hands. Many people with MPS I stand and walk with their knees and hips flexed. This, combined with a tight Achilles tendon, may cause them to walk on their toes. Some children with MPS I have knock-knees severe enough to require surgery.

Carpal tunnel syndrome

Some patients with MPS I may have poor hand function, in part as a result of carpal tunnel syndrome (median nerve entrapment).[2] This syndrome is due to pressure on the median nerve as a result of thickened ligaments within the wrist; it may cause pain, and loss of feeling in the fingertips, but most patients lack these typical symptoms (pain, tingling, or numbness).[3],[4],[5]  Because of the high incidence of the syndrome, routine electromyographic/nerve conduction velocity testing is typically recommended by the treating physician, even in the absence of patient complaints.[5]

Carpal Tunnel Credit: Illustration courtesy of the National MPS Society

Congenital abdominal/inguinal hernias with recurrence

In most individuals with MPS I, the abdomen bulges out due to their posture, weakness of the muscles, and the enlarged liver and spleen.[2]  Frequently, part of the abdominal contents will push out behind a weak spot in the wall of the abdomen, forming a hernia. The hernia can come from behind the navel (umbilical hernia) or in the groin (inguinal hernia). Inguinal (groin) hernias should be repaired by an operation, but hernias will sometimes recur. Mildly affected individuals with attenuated disease are less likely to have hernias.

HerniaCredit: Courtesy of Hodder/Arnold Publishers

Go Back


  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.