Serum dipeptidyl peptidase-IV: a better screening test for early detection of mucopolysaccharidosis?

Area of Science:

• Biochemistry
• Medical Diagnostics
• Genetics

Background:

• Mucopolysaccharidoses (MPS) are a group of rare genetic disorders.
• Accurate and early diagnosis is crucial for effective management and treatment.
• Current diagnostic methods can be complex and time-consuming.

Purpose of the Study:

• To evaluate the diagnostic performance of serum dipeptidyl peptidase-IV (DPP-IV) enzyme activity and urinary glycosaminoglycan (GAG)/creatinine (Cre) ratio in MPS diagnosis.
• To compare these markers with other biochemical indicators like chitotriosidase and adenosine deaminase (ADA) activities.
• To identify the most effective biomarkers for first-line MPS screening.

Main Methods:

• A case-control study involving 31 diagnosed MPS patients and 31 healthy controls.
• Measurement of serum DPP-IV enzyme activity, urinary GAG/Cre ratio, chitotriosidase activity, total ADA, and ADA-1 isoenzyme activity.
• Statistical analysis including correlation, ROC curve analysis, and univariate logistic regression.

Main Results:

• Serum DPP-IV enzyme activity and urinary GAG/Cre ratio were significantly elevated in MPS patients compared to controls (p<0.001).
• Strong correlations were observed between serum DPP-IV activity and urinary GAG/Cre ratio, as well as ADA-1 activity.
• Receiver operating characteristic (ROC) curve analysis indicated high diagnostic accuracy for both DPP-IV activity (AUC=0.988) and urinary GAG/Cre ratio (AUC=0.986).

Conclusions:

• Serum DPP-IV enzyme activity and urinary GAG/Cre ratio are highly sensitive and specific biomarkers for MPS diagnosis.
• These markers demonstrate superior diagnostic utility compared to chitotriosidase and ADA measurements.
• Serum DPP-IV enzyme activity, due to its lower susceptibility to age and hydration variations, can serve as a valuable complementary tool for first-line MPS screening alongside the urinary GAG/Cre ratio.