| ATP7B is a P-type ATPase required for copper homeostasis. In 1993, our laboratory discovered that defects in ATP7B cause Wilson disease (WND). Treatment of WND is effective, particularly when provided in the early stages of the disease. Mutation analysis is an important tool for reliable diagnosis of this clinically variable disease. Our laboratory has documented 518 ATP7B variants; (http://www.medicalgenetics.med.ualberta.ca/wilson/index.php ) however, only 50 have been functionally characterized. Functional studies are important for discriminating between normal and disease causing variants.;In my studies, a yeast model was used to study 21 ATP7B variants. I developed a 96-well plate version of the Fet3p (orthologue of human ceruloplasmin) oxidase assay that is more sensitive and time-efficient. The ATP7B variants were further analyzed using computational programs developed to distinguish normal from disease causing variants. These programs (PolyPhen, SIFT, and Align GVGD) use amino acid conservation and biochemical properties. PolyPhen and SIFT are useful tools for developing a hierarchical plan for selecting variants to be analyzed in future functional assays. |
