Molecular analysis of Wilson patients: direct sequencing and MLPA analysis in the ATP7B gene and Atox1 and COMMD1 gene analysis

ATP7B mutations result in Cu storage in the liver and brain in Wilson disease (WD). Atox1 and COMMD1 were found to interact with ATP7B and involved in copper transport in the hepatocyte. To understand the molecular etiology of WD, we analyzed ATP7B, Atox1 and COMMD1 genes. Direct sequencing of (i) ATP7B gene was performed in 112 WD patients to identify the spectrum of disease-causing mutations in the French population, (ii) Atox1 gene was performed to study the known polymorphism 5'UTR-99T>C in 78 WD patients with two ATP7B mutations and (iii) COMMD1 gene was performed to detect the nucleotide change c.492GAT>GAC. MLPA (Multiplex Ligation-dependent Probe Amplification) analysis was performed in WD patients presenting only one ATP7B mutation. Among our 112 WD unrelated patients, 83 different ATP7B gene mutations were identified, 27 of which were novel. Two ATP7B mutations were identified in 98 WD cases, and one mutation was identified in 14 cases. In two of these 14 WD patients, we identified the deletion of exon 4 of the ATP7B gene by MLPA technique. In 78 selected patients of the cohort with two mutations in ATP7B, we have examined genotype-phenotype correlation between the detected changes in Atox1 and COMMD1 genes, and the presentation of the WD patients. Based on the data of this study, no major role can be attributed to Atox1 and COMMD in the pathophysiology or clinical variation of WD.