Obesity as a Confounding Factor in the Diagnosis of Wilson's Disease: Case Report of Two Siblings with the Same Genotype but Different Clinical Courses.

Wilson's disease (WD) is a biallelic disease-causing variant in the ATP7B gene on chromosome 13q14.3 that results in copper accumulation in many organs, particularly the liver and brain. The phenotypic spectrum is wide and symptoms at onset can be heterogeneous. We describe two Sicilian siblings, a young man and his elder sister, both compound heterozygous for the variants c.1286-2A>G and c.2668G>A (p.Val890Met) in the ATB7B gene. The male patient presented with liver cirrhosis, which quickly progressed to end-stage liver disease (Child-Pugh score = C10), while his sister had moderate steatotic liver disease (SLD). Our findings highlight that SLD may not always be related to obesity in overweight patients, especially when there are other potential risk factors such as a family history of chronic liver disease, or the persistence of high transaminase despite the adoption of adequate dietary and pharmacological intervention. Screening for conditions such as WD could identify patients at risk of developing SLD and avoid delays in diagnosis. Phenotypic variability in WD is considerable; therefore, further studies are needed to identify which WD patients have a greater risk of developing SLD and determine factors that can predict the severity of the disease.