Wilson Disease may present symptomatically at any age although the majority presents between ages 5 and 35. It is also essential to screen the family of patients presenting with Wilson Disease because the chance of a sibling having the disease is 25%.

Wilson Disease patients often develop both liver and neuropsychiatric symptoms, none exclusive for Wilson Disease, which makes the diagnosis challenging. The diagnosis therefore needs to rely on the evaluation of a combination of biochemical markers and clinical symptoms.

Measuring copper levels in the body is a central part in diagnosing Wilson Disease, but the biochemical picture is complicated. Despite being a disease of excess copper, total serum copper is typically reduced in Wilson Disease patients compared to other individuals, due to the decreased levels of ceruloplasmin (as ATP7B ATPase cannot load copper onto ceruloplasmin and its half-life reduces). In contrast to the total copper level, ‘free’ (toxic) copper in the blood is normally increased.

As a consequence of copper overload, Kayser-Fleischer rings (deposits of copper around the iris, characteristic for Wilson Disease) may form, however they do not cause any symptoms and only a subset of Wilson Disease patients develops them.

Experts in Wilson Disease have developed a system for diagnosing Wilson Disease which includes an evaluation of biochemical and genetic data and clinical symptoms from individual patients. This method for diagnosis has been included in the European clinical practice guidelines for Wilson Disease.

Late diagnosis is the most common cause of death in Wilson Disease.