Background: Wilson disease results from heterogenous mutations within the ATP7B gene, which encodes the copper transporting enzyme ATPase 7B. H1069Q mutations account for up to 60% of identified mutations. So far there is a lack on data on the correlation of biochemical parameters of copper metabolism and the corresponding genotypes. Aim: The aim of this study was to assess and compare the results of ceruloplasmin [mg/dl], serum copper [μg/dl] and 24h urinary copper excretion [μg/24h] obtained before therapy of WD had been started, and mutational analysis. Patients and Methods: 31 patients (12F, 19M, aged 9-18) with mutations identified on both alleles were involved in this study. Eight patients were homozygous for H1069Q, 14 patients were heterozygous for H1069Q, and 9 patients carried mutations different from H1069Q. The results of biochemical parameters in copper metabolism were compared among the group of H1069Q homozygous patients vs. remaining ones, and among the group of patients carrying at least one H1069Q mutation vs. remaining ones, and among all three groups vs. each other. The t-test, U-test, ANOVA and Kruskal-Wallis tests were used in statystical analysis. Results: Patients homozygous for H1069Q had significantly higher serum copper concentrations (56.25 ± 13.47 vs. 32.44 ± 15.75; mean ± SD). Patients carrying at least one H1069Q mutation had higher ceruloplasmin (13.69 ± 8.35 vs. 4.53 ± 3.11) and copper (45.23 ± 13.7 vs. 18.78 ± 8.98) concentrations and lower 24h urinary copper excretion (169.22 ± 344.2 vs. 389.84 ± 490.23) than patients with no H1069Q mutation. Besides patients carrying no H1069Q mutation had lower ceruloplasmin (4.52 ± 3.12) and serum copper (18.78 ± 8.98) concentrations when compared with patients homozygous for H1069Q (14.98 ± 8.35 and 52.25 ± 13.47) as well as patients with one H1069Q mutation (12.96 ± 8.23 and 41.21 ± 12.56). Conclusions: Our data incline that the presence of at least one H1069Q mutation results in higher ceruloplasmin and serum copper concentrations and lower 24h urinary copper excretion in patients with WD. This may implicate that H1069Q WD carriers may present with less severe symptoms.