Fracture of the femur, fish odour, and copper deficiency in a preterm infant.

A preterm baby boy with blood and bone changes of copper deficiency is described. Copper deficiency was suspected after fracture of the left femur during examination of the hip joint. A low serum copper concentration (2.7 mumol/l; 17.2 micrograms/100 ml) and caeruloplasmin (0.04 g/l; 0.004 g/100 ml) confirmed the diagnosis. Despite the introduction of solids at 18 weeks the copper concentration remained low, and treatment with copper sulphate (2.5 mg daily) was started at 6 months. Treatment was stopped at 9 months, when he was both physically and developmentally normal. When given a choline-containing vitamin preparation (Ketovite) he developed a fish odour because of the accumulation of trimethylamine. Withdrawal of this preparation at 6 weeks and substitution with a choline-free preparation (Abidec) was soon followed by disappearance of the odour. It is speculated that prematurity rather than copper deficiency was responsible for the poor activity of liver enzyme, trimethylamine oxidase.