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Mucopolysaccharides are long chains of sugar molecules used in the building of the connective tissues in the body. The types of MPS are listed below with the most common types in bold. The bolded types will be discussed further:

  • MPS Type I – Hurler, Hurler-Scheie, and Scheie syndromes
  • MPS Type II – Hunter syndrome
  • MPS Type III – San Filipo syndromes
  • MPS Type IV – Morquio syndrome
  • MPS Type VI – Maroteaux-Lamy syndrome
  • MPS Type VII – Sly syndrome

Treatment for MPS – all types:

  • Enzyme replacement therapies can help increase the missing enzymes
  • Occupational therapy
  • Speech therapy
  • Physical therapy
    • Range of motion exercises help preserve joint function
    • Carpal tunnel exercises
  • Eye shades can help reduce glare from corneal clouding
  • Hearing aids may be appropriate
  • Gastrointestinal
    • Constipation and diarrhea can often be controlled by diet and possibly laxatives. 
MPS Type I – Hurler, Hurler-Scheie, and Scheie syndromes
  • MPS I is seen in all populations at a frequency of approximately 1:100,000 for the severe form and 1:500,000 for the attenuated form.
  • Types are based on age of onset and severity.
    • Hurler (This is the most severe type of MPS Type I.) Possible findings:
      • Progressive skeletal dysplasia
      • Coarsening facial features
      • Corneal clouding
        • Can lead to significant vision disability
      • Hearing loss is common
      • Death usually by year 10
      • Cardiac involvement
      • Gastrointestinal; diarrhea and constipation
      • Intellectual disability is progressive and profound
      • Limited language skills
    • Attenuated MPS Type I (Hurler-Scheie and Scheie) (These are less severe than Hurler syndrome.) Possible findings:
      • Skeletal and joint are significant sources of disability and discomfort
      • Scoliosis
      • Back pain
      • Many have normal or near normal intellect
      • Some have learning disabilities
      • Sleep apnea
      • GI: hernias
      • Respiratory: progressive pulmonary disease
      • Hearing loss
        • Moderate to severe hearing loss
      • Cardiac valvular disease
      • Short stature
      • Enlarged spleen (hepatomegaly)
      • Corneal clouding
        • Can lead to significant vision disability
MPS Type II – Hunter syndrome
  • Incidence is approximately 1 in 100,000 births.
  • Primarily affects males with females being carriers, but rarely a female can be affected.
  • Varies from severe to attenuated
  • Symptoms of the severe form resemble the features seen in Hurler syndrome (MPS Type 1)
  • Symptoms of the attenuated type resemble the features seen in the more attenuated MPS Type 1 (Hurler-Scheie and Scheie syndromes) although the facial features may be coarser in Hunter.
  • Intelligence can be normal or can be affected in the more severe form.
Mucopolysaccharidosis Type IV (MPS Type IV): Morquio syndrome
  • Coarsening of the facial features
  • Skeletal deformities
    • Carpal tunnel syndrome
    • Joint stiffness
  • Abnormal walk
  • Breathing problems
  • Eye problems
  • Hearing loss
  • Dental problems
  • Enlarged liver and spleen
  • Juvenile form (early-onset, severe form):
    • Mental function declines
    • Typically severe intellectual disability
    • Aggressive behavior and hyperactivity
    • Spasticity
  • Late (mild) form:
    • Mild to no mental deficiency