Mucopolysaccharidosis (MPS) Physical Symptom Score: Development, Reliability, and Validity.

Area of Science:

• Medical research
• Rare diseases
• Symptomology

Background:

• Mucopolysaccharidoses (MPS) are rare genetic disorders impacting multiple organ systems.
• Accurate assessment of somatic disease burden is crucial for research and treatment monitoring in MPS.
• Existing measures may not fully capture the comprehensive disease impact in MPS type I.

Purpose of the Study:

• To develop and validate the Physical Symptom Score (PSS) for quantifying somatic disease burden in MPS.
• To assess the reliability, concurrent validity, and age-related changes of the PSS in MPS type I.
• To evaluate the PSS's relationship with daily living skills and quality of life.

Main Methods:

• Developed the PSS by summing frequency and severity of organ involvement, surgeries, and hydrocephalus from medical histories.
• Recruited 54 patients with MPS I (Hurler syndrome and attenuated MPS I) aged 5-18 years for longitudinal study over 5 years.
• Assessed concurrent validity using the Vineland Adaptive Behavior Scale (DLS) and Child Health Questionnaire (CHQ).

Main Results:

• The PSS demonstrated an association with age in both MPS I groups, indicating increased disease burden over time.
• A significant negative correlation was observed between PSS and DLS (r = -0.48) and CHQ (r = -0.55) in the attenuated MPS I group.
• This association was not significant in the Hurler syndrome group, suggesting potential differences in disease manifestation or response to treatment.

Conclusions:

• The PSS is a valuable tool for measuring disease burden and treatment effects in attenuated MPS I.
• The PSS's correlation with daily living skills and quality of life highlights its clinical relevance.
• Adaptations to the PSS may be necessary for the Hurler syndrome population due to factors like early transplant and differing expectations.