Cognitive impairment in stable Wilson disease across phenotype

Background: In Wilson disease (WD), mutations in the gene encoding the ATP7B copper transport protein causes accumulation of copper especially in liver and brain. WD typically presents with hepatic and/or neuropsychiatric symptoms. Impaired cognition is a well-described feature in patients neurological WD, while the reports on cognition in hepatic WD patients are fewer and less conclusive. We examined cognition in a cohort of WD patients with both phenotypes. Methods: In this cross-sectional pilot study, we investigated cognition in 28 stable Danish WD patients by portosystemic encephalopathy (PSE) and continuous reaction time (CRT) tests. Half of the patients were female and median age was 35.5 years (IQR 24.5). The phenotype was hepatic in 14 (50%), neurologic in 10 (36%) and mixed in 4 4 (14%). The duration of treatment was >2 year in all patients, and the condition stable as judged by urinary copper excretion, liver enzymes, and clinical assessment.Results: In total, 16 (57%) patients performed worse than normal in the PSE and/or CRT tests. The two tests correlated (rho=0.60, p=0.0007) with each other, but neither correlated with phenotype, MELD-, Child-Pugh score, 24h-U-Cu, or treatment type.Conclusion: Measurable cognitive impairment was present in more than half of the stable WD patients independent of phenotype. Thus, our data questions the existence of a purely hepatic phenotype.