Which of the following is a common clinical sign of Wilson's disease?

In Wilson's disease, a key clinical sign is the presence of Kayser-Fleischer rings, which are deposits of copper that accumulate in the cornea. These rings are a result of abnormal copper metabolism and are often visible upon slit-lamp examination of the eyes. The copper deposits impart a greenish or golden-brown coloration at the corneal margin, which is a hallmark finding in patients with this condition. The identification of Kayser-Fleischer rings can aid in the diagnosis of Wilson's disease, particularly when it is suspected in younger patients with liver dysfunction or neurological symptoms.

While other symptoms such as joint pain, abdominal pain, and weight loss can occur in patients with Wilson's disease, they are not as distinctive or characteristic as Kayser-Fleischer rings for this specific disorder. Consequently, recognizing these rings provides critical diagnostic information, making it an essential sign of Wilson's disease.