Clinical features and outcome in patients with osseomuscular type of Wilson's disease.

Background: Wilson's disease with osseomuscular type is a rare condition, which often lacks typical hepatic and neurological symptoms and causes misdiagnoses easily. During the past 10 years, eight Chinese patients of osseomuscular type of Wilson's disease were identified in our clinic.
Methods: Clinical information was gathered from medical records and follow-ups. The genetic testing was performed in each patient. Serum ceruloplasmin, Kayser-Fleischer rings, liver function, brain magnetic resonance imaging and abdominal ultrasonography were also evaluated.
Results: The median age of onset is 12 years of age. The patients had their initial musculoskeletal conditions with arthralgia or joint deformity, while the hepatic or neurologic signs were minimal. Most patients (6/8) eventually developed clinical neurological symptoms afterwards with a median interval of 36 months. All of them had normal liver function and low serum ceruloplasmin (<0.1 g/L). Most patients (6/8) present with Kayser-Fleischer rings and abnormal hepatic ultrasonography. The arthralgia was resolved with copper chelation therapy.
Conclusions: Wilson's disease with osseomuscular type occurs without typical hepatic or neurological symptoms, which makes the clinical diagnosis challenging. Serum ceruloplasmin, abdominal ultrasonography, ophthalmic examination and genetic testing help to establish the diagnosis. Early diagnosis can initiate an effective treatment and prevent the further damage.