Re-evaluation of the diagnostic criteria for Wilson disease in children with mild liver disease

Abstract

The diagnosis of Wilson disease (WD) is challenging, especially in children. Early detection is desirable in order to avoid dramatic disease progression. The aim of our study was to re-evaluate in WD children with mild liver disease the conventional diagnostic criteria and the WD scoring system proposed by an international consensus in 2001. Forty children with WD (26 boys and 14 girls, age range = 1.1-20.9 years) and 58 age-matched and sex-matched patients with a liver disease other than WD were evaluated. Both groups were symptom-free and had elevated aminotransferases as predominant signs of liver disease. In all WD patients, the diagnosis was supported by molecular analysis, the liver copper content, or both. A receiver operating characteristic (ROC) analysis of ceruloplasmin at the cutoff value of 20 mg/dL showed a sensitivity of 95% [95% confidence interval (CI) = 83%-99.4%] and a specificity of 84.5% (95% CI = 72.6%-92.6%). The optimal basal urinary copper diagnostic cutoff value was found to be 40 μg/24 hours (sensitivity = 78.9%, 95% CI = 62.7%-90.4%; specificity = 87.9%, 95% CI = 76.7%-95%). Urinary copper values after penicillamine challenge did not significantly differ between WD patients and control subjects, and the ROC analysis showed a sensitivity of only 12%. The WD scoring system was proved to have positive and negative predictive values of 93% and 91.6%, respectively. Urinary copper excretion greater than 40 μg/24 hours is suggestive of WD in asymptomatic children, whereas the penicillamine challenge test does not have a diagnostic role in this subset of patients. The WD scoring system provides good diagnostic accuracy.