Longitudinal Study of Bone Disease in Children With Mucopolysaccharidoses (MPS) I, II, and VI

• Annual change in Peripheral quantitative computer tomography (pQCT) [ Time Frame: baseline, year 1, year 2, year 3 ] [ Designated as safety issue: No ]
  Measurement of volumetric bone density, bone geometry, bone strength, and muscle fat
• Annual change in Biomarkers of bone remodeling [ Time Frame: baseline, year 1, year 2, year 3 ] [ Designated as safety issue: No ]
  Measurements of bone turnover
• Annual change in Biodex [ Time Frame: baseline, year 1, year 2, year 3 ] [ Designated as safety issue: No ]
  Measurement of muscle strength
• Annual change in Endocrine function tests [ Time Frame: baseline, year 1, year 2, year 3 ] [ Designated as safety issue: No ]
  Thyroid function, growth factor levels, pubertal hormones, vitamin D
• Annual change in growth measurements [ Time Frame: baseline, year 1, year 2, year 3 ] [ Designated as safety issue: No ]
  sitting and standing heights, arm and tibial length

Mucopolysaccharidoses (MPS) I, II, and VI are a group of rare, lysosomal storage disorders in which certain enzymes are missing that are normally required for breaking down specific complex carbohydrates.

Deficiencies in these enzymes result in the build-up of toxic substances in various tissues and cause damage to the body's organs. In the past, children diagnosed with MPS I, II, or VI frequently died in early to late childhood. Recent advances in treatments including hematopoietic cell transplantation (HCT) and enzyme replacement therapy (ERT) have been helping children with these disorders live into adulthood.

Although it appears that poor growth and abnormal bone development persist, this has not yet been well studied. Researchers would like to know more about the long-term course of MPS I, II, and VI. Therefore, the purpose of this study is to learn more about growth, bone disease and endocrine dysfunction in children with MPS I, II and VI over time. This information is needed to:

1. determine long-term benefits and limitations of current treatments including HCT or ERT
2. direct development of further treatment options
3. improve clinical care for children affected by the disorders

community sample

Inclusion Criteria:

• Diagnosis of MPS I, II, or VI
• Ability to travel to study center for evaluations.
• Age ≥ 5 years and < 18 years: age at entry into study must be ≥5 years and ≤16 years to ensure a minimum of 2 study visits.

Exclusion Criteria:

• Pregnancy (will be determined at each study visit)
• Participation in any other study within the past 12 months which would result in increasing the child's radiation exposure above 500 mrem for the calendar year.
• Participants who cannot comply with study procedures or have other factors that would inhibit their participation as determined by the PI's discretion.

• Children's Hospital & Research Center Oakland
• University of Utah