Selimoglu MA et al. (2008) Bone mineral density of children with Wilson disease: efficacy of penicillamine and zinc therapy. J Clin Gastroenterol 42: 194–198

Osteoporosis is a common complication of chronic liver disease. Although bone demineralization has been noted in Wilson's disease—which involves pathologic copper accumulation—the exact prevalence of osteopenia and osteoporosis in affected patients is unknown. Selimoglu et al. compared the bone mineral density (BMD) and bone mineral content (BMC) of children with Wilson's disease with those of healthy controls matched for age and sex. The effect on BMD and BMC of standard therapies for Wilson's disease was also investigated.

The study included 31 children (10 girls) aged 2–16 years with Wilson's disease and 16 controls. Patients had significantly lower mean BMD, BMC and Z-scores (a measure of how far BMD deviates from normal) than controls: BMD 0.52 vs 0.72 (P = 0.001), BMC 19.27 vs 29.67 (P = 0.009), and Z-score −2.33 vs −0.12 (P = 0.001), respectively. The prevalence of osteopenia and osteoporosis was 22.6% and 67.7%, respectively, in children with Wilson's disease. Therapy with penicillamine (a copper chelator) and zinc (which inhibits copper absorption) had no effect on BMD or BMC after 1 year of treatment.

Most patients in the study had high renal tubular phosphate excretion and/or hypercalciuria. Copper deposition is thought to cause tubular dysfunction in Wilson's disease. The authors note that 2 years of penicillamine treatment are normally required for recovery of tubular function; continued penicillamine treatment might, therefore, eventually reduce bone mineral loss. Nevertheless, BMD screening and alternative antiosteoporosis therapies are needed for children with Wilson's disease.