Laboratory and clinical evaluation of a microarray for the detection of ATP7B mutations in Wilson disease in China

Abstract

Background and objective: Wilson disease (WD) is an autosomal recessive copper metabolic disorder caused by mutations in ATP7B. Sanger sequencing is currently used for ATP7B variant identification. However, the ATP7B gene contains 21 exons, which makes sequencing of the entire gene both complex and time-consuming. Therefore, a simpler assay is urgently needed.

Methods: We performed a laboratory and clinical evaluation of an oligonucleotide microarray for the detection of 24 ATP7B recurrent mutations (except p.P992L) in Chinese patients with WD.

Results: The accuracy of the microarray was evaluated by screening for ATP7B mutations in 126 patients including 106 suspected WD samples and 20 patients with other liver diseases as negative control. Results were confirmed by Sanger sequencing. We established a reliable microarray system for the rapid detection of the 24 ATP7B mutations, with a sensitivity of 30 ng/test genomic DNA and specificity of 100% for all loci; the coefficient of variation in repeatability tests was <10%. Clinical evaluation showed an overall concordance between the microarray detection and sequencing of 100%, and 81.13% (86/106) of suspected WD cases showed ATP7B mutations by microarray detection. Microarray and Sanger sequencing identified p.R778L (50.94%), p.A874V (17.92%), p.P992L (11.32%), p.V1106I (11.32%), and p.I1148T (6.60%) as the most common mutations in WD patients.

Conclusions: Our microarray system is customizable and easily used for high-throughput detection of certain recurrent ATP7B mutations, providing a simpler method suitable for WD genetic diagnosis in China.

Keywords: ATP7B; DNA microarray; Wilson disease; mutation detection.