Identification and analysis of mutations of the Wilson disease gene in Chinese population

Abstract

Objective: To investigate the characteristics of mutations in exon 3-20 of Wilson disease (WD) gene and their consequences in Chinese population.

Methods: Sixty unrelated normal Chinese and forty-four unrelated WD patients were studied. Genomic DNA was prepared from peripheral blood leukocytes by a salt-out method. Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and subsequently direct sequencing were used to identify the mutations and polymorphisms of WD gene.

Results: Ten different mutations have been found, accounting for 52% of the mutant genes. Five of them are identified as novel missense mutations. Mutations Arg778Leu, Thr935Met and Ala874Val were represented respectively in 28.4%, 6.8% and 3.4% of WD chromosomes. The remaining mutations were found rare and limited to one or two patients. A total of 11 patients were homozygous for a single mutation, and 17 patients were in a compound heterozygous state with or without a known mutation.

Conclusion: In Chinese, WD seems to result from two or three relatively common mutations and a large number of rare mutations. Arg778Leu and Thr935Met might be hotspots of mutation in Chinese population. The results indicated that the feature of mutations of WD gene is different between Chinese and the Western. Instead of exon 14 and exon 18, we had to select exon 8 and exon 12 first to detect mutations of WD gene in Chinese. It is of great importance to establish a direct diagnostic method for WD. This study improves our knowledge on functional domains of the WD gene, and helps elucidate the wide spectrum of manifestations of the disease as well.