Mucopolysaccharidoses (MPS)

What You Need to Know

  • The term mucopolysaccharidoses refers to a number genetic conditions that cause sugar to be excreted in urine.
  • Most cases of mucopolysaccharidoses are diagnosed after a child is 12 months old.
  • A physical exam and diagnostic tests, including a urine test, are used to diagnose mucopolysaccharidoses.
  • Treatment for mucopolysaccharidoses depends on the associated orthopaedic conditions also present in the patient.

What is mucopolysaccharidoses?

Mucopolysaccharidoses is a group of genetic disorders — Hurler; Hunter; Sanfilippo A, B, C and D; Morquio A, B and C; and Maroteaux–Lamy — characterized by the excretion of mucopolysaccharide (sugar) in the urine. Most are recessive disorders, meaning passed on by both parents, and are difficult to diagnosis at birth through the infant’s first year.

This group of disorders involves a deficiency of lyosomal, an enzyme that degrades certain products in the body. Without this enzyme, these products begin to accumulate in the body over time and are stored in the brain, organs and joints.

What are the symptoms of mucopolysaccharidoses?

Individuals with mucopolysaccharidoses are short-statured and have stiff joints, especially in the hands. Some types of the disorders may also cause corneal clouding, and progressive intellectual delay is seen in children with Hurler syndrome.

Orthopaedic Conditions Seen in Patients with Mucopolysaccharidoses

Orthopaedic conditions common among patients with mucopolysaccharidoses include: 

  • Misalignment of the limbs: knock knee or bowing of the legs
  • Abnormalities of the upper cervical spine
  • Kyphosis
  • Carpal tunnel and trigger fingers

Mucopolysaccharidoses Diagnosis

The doctor makes the diagnosis of mucopolysaccharidoses with a complete medical history, physical examination and diagnostic tests. Diagnostic procedures may include:

  • Urine test: toluidine blue-spot test; if positive, will need to have further genetic testing
  • X-rays of the cervical, thoracic and lumbar spine, and lower extremities

Mucopolysaccharidoses Treatment

Treatment for mucopolysaccharidoses varies depending on the associated orthopaedic conditions that present in the patient. For example:

  • Bone marrow transplant for Hurler
  • Osteotomies (cuts in the bone to correct alignment)
  • Guided growth for lower extremity misalignment, such as knock knee
  • Cervical fusion with halo to correct instability and underdevelopment
  • Posterior spinal fusion to correct kyphosis


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