Post-mortem atomic absorption spectrophotometry of the myocardium of a 14-year-old boy revealed a hundred-fold increase in copper. Further electrolyte analysis of the myocardium showed changes corresponding to metabolic heart muscle damage. Ultrastructural examination showed all the feature of a cardiomyopathy at the cellular level. Laser-Microprobe-Mass-Analysis demonstrated an inhomogeneous distribution of copper. An essential factor in the mechanism of death is heart damage.