Wilson disease and idiopathic copper toxicosis.

The pathogenic agent of both Wilson disease (WD) and non-Indian childhood cirrhosis (which we term idiopathic copper toxicosis, or ICT) is copper accumulating to excess in the liver. Inheritance of a pair of alleles of an autosomal recessive gene on chromosome 13 is necessary and sufficient to cause such copper accumulation in WD; reducing the dietary intake of copper cannot prevent the development of WD. In contrast, the lethal accumulations of copper in children with ICT have been attributed primarily to an increased dietary intake of copper. However, 64 124 child-year exposures of children under the age of 6 y to drinking water containing a copper concentration of approximately 125.9 micromol/L (8 mg/L) produced no deaths from any form of liver disease. Moreover, the ICT of seven infants was attributed primarily to drinking water containing < 110.2 micromol Cu/L (7 mg/L) despite evidence of the presence of a genetic defect in three of the patients, one of whom was exclusively breast-fed. These data suggest that ICT cannot be caused solely by increased dietary intake of copper and occurs only in children with an identified genetic defect.