Neurological Wilson's disease without hepatic involvement in an adolescent female

A female adolescent presented with a 9 month history of progressive involuntary movements, initially manifesting as finger tremors and evolving into flinging motions of the extremities, resulting in an inability to walk over the last 4 months. Concurrently, she developed dysarthria. Neurologically, she exhibited normal power, rigidity and brisk deep tendon reflexes, with a downgoing plantar reflex. Contrast-enhanced MRI revealed hyperintensity in bilateral caudate lobes, basal ganglia and pons, indicative of Wilson's disease. Liver function tests and ultrasound were normal while Kayser-Fleischer rings were confirmed by slit lamp examination. Serum ceruloplasmin was low, 24-hour urine copper was elevated (125.5 mcg) and whole exome sequencing identified a heterozygous ATP7B mutation, confirming the diagnosis. Isolated neurological involvement without hepatic involvement is an extremely rare presentation and needs clinical expertise to delineate Wilson's disease as a possible aetiology.