WILSON disease’s genetics gap is narrowing, with new data showing that most previously unexplained cases can be traced back to overlooked or misclassified variants in the ATP7B gene.
Wilson disease (WD) is a rare inherited disorder in which impaired function of the ATP7B copper transport protein leads to copper accumulation, primarily in the liver and brain. This can result in hepatic, neurological, and psychiatric symptoms, with delayed diagnosis linked to worse outcomes.
Although genetic testing is central to diagnosis, a proportion of clinically confirmed cases have remained genetically unexplained.
Genetic Blind Spots in Wilson Disease Shrink
In a cohort of 761 patients with WD, 5.8% had zero or only one recognised disease-causing ATP7B variant despite meeting diagnostic criteria based on a Leipzig score of at least 4. Historically, such gaps have raised questions about whether other genes or mechanisms might contribute to the disease.
The latest analysis challenges that uncertainty. By applying updated genomic and functional tools, researchers resolved more than half of these ambiguous cases and found no evidence of alternative monogenic causes.
Advanced Sequencing Boosts Diagnostic Yield
Among 44 genetically unresolved patients, whole genome sequencing and variant reclassification identified pathogenic ATP7B variants in 52% of cases. A further six patients were confirmed through ATP7B peptide analysis, which demonstrated protein dysfunction and supported the pathogenic role of previously uncertain variants.
Overall, these combined approaches confirmed ATP7B dysfunction in 66% of previously unresolved cases. Across the full cohort, this translated to genetic confirmation in 98% of patients.
The study also included extensive screening of 97 copper-related genes 4,304 genes linked to liver or neurological disorders. This broader analysis did not reveal any alternative genetic explanations.
Clinical Implications for Diagnosis and Follow-Up
The findings reinforce WD as a single-gene disorder driven by ATP7B, rather than a genetically heterogeneous condition. For clinicians, this has direct implications for diagnostic pathways, particularly in patients with strong clinical suspicion but inconclusive genetic results.
The data supports routine re-evaluation of genetic findings using contemporary sequencing methods, alongside functional assays such as peptide analysis where available. This approach may improve diagnostic certainty, enable more accurate genetic counselling, and facilitate cascade testing in families.
Remaining Gaps and Practical Considerations
Not all advanced analyses were feasible in every patient, and a small proportion of cases remain genetically unresolved. However, the study highlights that revisiting earlier negative or inconclusive genetic results can substantially reduce diagnostic uncertainty.
For healthcare professionals managing Wilson disease, the message is clear: before considering alternative diagnoses, re-examining ATP7B with modern tools may provide the missing answer.
Reference
Lildballe DL et al. Wilson disease is a single gene disorder – comprehensive analysis of patients with prior negative genetic testing. JHEP Reports. 2026;DOI: 10.1016/j.jhepr.2026.101815.
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