Myeloneuropathy is a possible feature of deficiency in which trace element?

• A. Selenium
• B. Zinc
• C. Copper
• D. Iron

Answer: (C)

Copper deficiency can cause a myeloneuropathy because copper is essential for enzymes involved in myelin formation and neuronal energy production. When copper is lacking, the dorsal columns and lateral corticospinal tracts of the spinal cord can degenerate, producing sensory ataxia, paresthesias, weakness, and spasticity that resemble subacute combined degeneration. This neurologic syndrome is a well-recognized feature of copper deficiency and can arise from poor intake, malabsorption, or excessive zinc intake which disrupts copper absorption. By contrast, deficiencies of selenium, zinc, or iron produce different clinical pictures (cardiomyopathy and myopathy for selenium; growth, skin, and immune issues for zinc; anemia for iron) and do not classically present with myeloneuropathy. Treating copper deficiency with repletion can improve or reverse neurologic symptoms if caught early.