Copper is now well established as an essential trace element. The major circulating form, caeruloplasmin, synthesised in the liver. It is an acute phase reactant and can increase greatly in response to infection, injury, chronic inflammatory conditions or steroid hormones (pregnancy, certain contraceptive pills and oestrogen therapy).
Serum copper and caeruloplasmin are both increased in these circumstances. Excess copper is excreted in the bile, only small amounts being found in urine, unless renal damage is present, or substances which bind copper are excreted.
Copper deficiency presents as a microcytic hypochromic anaemia with marked neutropenia, which is resistant to iron therapy. Children and neonates on diets deficient in copper have ineffective collagen synthesis, and may develop bone disease. Reduced copper absorption is common in diarrhoea and when zinc intake is increased.
Wilson’s disease is an autosomal recessive disorder, the frequency being of the order of 1 in 100,000 live births. Copper cannot be excreted via the bile, or incorporated into caeruloplasmin, and consequently accumulates within the liver. Later it is probable that the copper ‘overflows’ and accumulates more slowly in other tissues, especially the brain.
The classical presentation is of adults with progressive neurological symptoms, low serum concentrations of copper and caeruloplasmin, raised urinary copper excretion, and characteristic copper deposits in the corneas (Kayser – Fleischer rings).
- Up to 4 months old: 1.4 – 7.2µmol/L
- 4 to 6 months old: 3.9 – 17.3µmol/L
- 6 months to 9 years old: 11.1 – 27.4µmol/L
- 9 years to 13 years old: 11.2 – 23.7µmol/L
- 13 years to 19 years old: 11 – 22.5µmol/L
- 19 years old and above: 11 – 25.1µmol/L
Dark blue topped sodium heparin (trace element tube) specimen required.
Special Biochemistry, Freeman Hospital, Newcastle-upon-Tyne