Exchangeable copper for patients with Wilson disease at follow-up: Rethinking normal ranges or changing methodology.

Area of Science:

• Hepatology
• Clinical Chemistry
• Metabolic Disorders

Background:

• Wilson disease monitoring relies on urinary copper and liver markers.
• Exchangeable copper (CuEX) was proposed to assess the free copper pool.
• Validation of CuEX target ranges for Wilson disease is needed.

Purpose of the Study:

• To evaluate CuEX quantification in Wilson disease patients.
• To assess CuEX reliability in real-world clinical practice over two years.

Main Methods:

• Collected 213 CuEX samples from 92 Wilson disease patients.
• Classified patients as stable or nonstable based on diagnosis duration and treatment adherence.
• Compared CuEX levels with therapy, time since diagnosis, and clinical stability.

Main Results:

• 57% of CuEX measurements were below normal ranges.
• No association found between CuEX levels and therapy, time from diagnosis, or stability.
• Only 23.4% of CuEX samples correlated with urinary copper excretion.

Conclusions:

• CuEX alone is suboptimal for assessing copper homeostasis in Wilson disease.
• Caution is advised when using CuEX without additional clinical data.
• Normal reference intervals for CuEX in treated Wilson disease patients require redefinition.