False positive autoimmune markers and elevated immunoglobulin G in genetically confirmed Wilson disease.

Wilson disease (WD) and autoimmune hepatitis (AIH) are leading causes of chronic liver disease in children and often present with overlapping clinical and immunological features, complicating early diagnosis. This retrospective study evaluated serum immunoglobulin G (IgG) and autoantibody profiles in 79 genetically confirmed, treatment-naive pediatric WD patients compared with 112 AIH controls. Elevated IgG (>1.1× upper limit of normal) was observed in 82.3% of WD patients, while 31.5% tested positive for at least one autoantibody, including anti-smooth muscle antibody, anti-nuclear antibody, and anti-liver kidney microsomal. Notably, 20.2% of WD patients met the simplified diagnostic criteria for AIH. Compared to AIH, WD patients had significantly lower IgG levels and less frequent autoantibody positivity. Histology revealed distinguishing features, with WD showing more steatosis and ballooning but less interface hepatitis and plasma cell infiltration. These findings highlight the potential for diagnostic misclassification. Comprehensive evaluation, including histology and genetic testing, remains critical to differentiate WD from AIH and guide appropriate therapy.