Wilson's Disease (WD) is a common metabolic disorder predominantly involving liver, brain, and eyes. Pancreatic, renal, psychiatric, and cardiac involvement have also been described. No single investigation can be considered diagnostic of WD; therefore, diagnosis is based upon a series of tests best interpreted using Wilson disease diagnostic index (WDDI). We present a difficult-to-diagnose, 9-year girl of consanguineous parents, with chronic liver disease and portal hypertension. Initial workup was equivocal with significantly low serum ceruloplasmin, normal urinary copper excretion and absent Kaiyser-Fleischer (KF) rings. Diagnosis was established by ATP7B mutation analysis. The patient was found homozygous for c.3955C>T (p.Arg1319Ter) in exon 19, a rare mutation described in literature, which results in premature truncation of peptide chain. Key Words: ATP7B, Wilson disease, Copper, Mutations, Hepatolenticular degeneration.