This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Kayser-Fleischer ring will be present in what propoion of patients with neurologic manifestations of wilson disease? 
Select and explain. 
A. Almost 100 %, B. Less than 10 %, C. 30-50 %, D. 20-30 %
A: Almost 100 %
Answer: A: Almost 100 % 
Explanation: Kayser-Fleischer rings diagnosed definitively by an ophthalmologist using a slit lamp. They are present in >99% of patients with neurologic/psychiatric forms of wilson. Kayser-Fleischer rings are present in only 30-50% of patients diagnosed in the hepatic or presymptomatic state of wilson disease. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 3188