Novel ATP7B gene mutations in Chinese Han patients with hepatolenticular degeneration

R74; BACKGROUND: ATP7B gene exon 8 Arg778Leu and exon 12 Arg952Lys are gene mutation hot spots in Chinese Han patients with hepatolenticular degeneration, or Wilson's disease (WD). However, the gene fragments are too short for detection and the mutation detection rate remains low.OBJECTIVE: To analyze DNA sequences of ATP7B gene exon 8-exon 9 and exon 10-exon 12 sections. DESIGN, TIME AND SETTING: A concurrent, non-randomized, controlled, genetic polymorphism study was performed at the Anhui Medical Genetics Center, Anhui, China from March to July in 2009.PARTICIPANTS: Fifty patients, who were admitted to the Department of Neurology at the First Affiliated Hospital of Anhui Traditional Chinese Medical College between March and July in 2009, were diagnosed with WD. The WD group comprised 32 males and 18 females, with an average age of (18.8 ± 8.3) years. WD was confirmed by clinical observation, as well as physical, imaging, and biochemical examinations, including testing for serum copper, ceruloplasmin, and copper oxidase. The control group comprised 20 normal subjects, who underwent physical examination at the First Affiliated Hospital of Anhui Traditional Chinese Medical College, and included 13 males and 7 females, with an average age of (27.9 ± 2.4) years. All subjects were Chinese Han population.METHODS: Genomic DNA was extracted from 50 WD patients and 20 normal controls. Polymerase chain reaction amplification of ATP7B gene exon 8-exon 9 (about 1 100 bp) and exon 10-exon 12 (about 850 bp) segments was performed. DNA exon-intron amplification products from all subjects were processed through direct bidirectional sequencing, and sequencing results were analyzed. MAIN OUTCOME MEASURES: Sequence changes of ATP7B gene exon 8-exon 9 and exon 10-exon 12 segments.RESULTS: In the 50 included WD patients, ATP7B gene intron 8 nt53592A → G with nt53671G → A homozygous mutation was detected between exon 8-exon 9 in seven cases; exon 8 Arg778Leu mutations with Leu770Leu synonymous mutation was detected in four cases; exon 11 Gly790Arg heterozygous missense mutation between exon 10-exon 12 was found in four cases; exon 12 Arg952Lys heterozygous missense mutation was seen in 11 cases; and two additional cases were associated with exon 12IIe929Val polymorphism.CONCLUSION: ATP7B gene intron 8 mutation is a possible pathogenic mutation that is associated with WD pathogenesis. The exon 11 mutation rate accounts for 8% of all WD patients, and the very few previously rep