Novel mutations of the ATP7B gene in Han Chinese families with pre-symptomatic Wilson's disease

Zhe-Feng Yuan, Wei Wu, Yong-Lin Yu, Jue Shen, Shan-Shan Mao, Feng Gao, Zhe-Zhi Xia

Hangzhou, China

Author Affiliations: Department of Neurology (Yuan ZF, Yu YL, Shen J, Mao SS, Gao F, Xia ZZ), Department of Endocrinology (Wu W), Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China

Corresponding Author: Yong-Lin Yu, Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, 57 Zhugan Xiang, Hangzhou 310003, China (Tel: +86-571-88873682; Fax: +86-571­87074655; Email: yuyonglin1998@163.com)

doi: 10.1007/s12519-015-0031-5

Background: Wilson's disease (WD) is an autosomal recessive genetic disorder of copper metabolism, caused by mutations in the ATP7B gene, resulting in copper accumulation in the liver, brain, kidney, and cornea and leading to significant disability or death if untreated. Early diagnosis and proper therapy usually predict a good prognosis, especially in pre-symptomatic WD. Genetic testing is the most accurate and effective diagnostic method for early diagnosis.

Methods: The clinical and biochemical features of three unrelated Han Chinese families with pre-symptomatic WD were reported. The molecular defects in these families were investigated by polymerase chain reaction and DNA sequencing. Hundred healthy children with the same ethnic background served as controls. Bioinformatic tools (polymorphism phenotyping-2, sorting intolerant from tolerant, protein analysis through evolutionary relationships, and predictor of human deleterious single nucleotide polymorphisms) were combined and used to predict the functional effects of mutations.

Results: We identified 2 novel ATP7B mutations (p.Leu692Pro and p.Asn728Ser) and 3 known mutations (p.Met769fs, p.Arg778Leu and p.Val1216Met) in these Chinese WD families. These mutations were not observed in the 100 normal controls. The bioinformatic method showed that p.Leu692Pro and p.Asn728Ser mutations are pathogenic.

Conclusions: Our research enriches the mutation spectrum of the ATP7B gene worldwide and provides valuable information for studying the mutation types and mode of inheritance of ATP7B in the Chinese population. Liver function analysis and genetic testing in young children with WD are necessary to shorten the time to the initiation of therapy, reduce damage to the liver and brain, and improve prognosis.

                                                                                                  World J Pediatr 2015;11(3):255-260

Key words: ATP7B; Chinese; mutation; Wilson's disease