115例肝豆状核变性患者的基因型-表型关系和遗传学研究

Genotype-phenotype relationship and genetics study of 115 cases with Wilson's disease

目的:探讨肝豆状核变性(WD)的基因型-表型关系,研究ATP7B基因突变谱。方法:回顾性分析2015年至2022年在郑州大学第一附属医院确诊的115例WD患者的临床资料和基因检测结果。计量资料比较采用秩和检验,计数资料比较采用χ^(2)检验;采用多因素logisitc回归法分析患者基因型和表型的相关性。结果:以肝脏表现起病的(肝型)占60.9%,神经系统症状起病的(脑型)占13.0%,肝脑混合型占26.1%。症状前个体占肝型的62.9%。二代测序诊断WD的占87.8%,联合多重连接探针扩增技术诊断WD的占89.6%,仅检测到1个致病位点的占10.4%。基因检测结合临床资料对WD的诊断率为100%。共检出ATP7B变异76种,突变频率最高前3位的为c.2333G>T(p.Arg778Leu,30.7%)、c.2975C>T(p.Pro992Leu,7.3%)和c.2621C>T(p.Ala874Val,6.4%)。变异主要分布在第8、11~13和15~18号外显子,占变异总数的90%以上。发现新变异8个,分别为c.3724G>A(p.Glu1242Lys)、c.3703G>C(p.Gly1235Arg)、c.3593T>C(p.Val1198Ala)、c.2494A>C(p.Lys832Gln)、c.1517T>A(p.Ile506Lys)、c.484G>T(p.Glu162Ter)、c.1870-49A>G和第10~21号外显子缺失。肝组织病理学示细胞水肿变性、炎性和坏死,铜染色阳性率仅为42.8%。基因型-表型分析显示,携带p.Arg778Leu变异者比携带其他变异者的丙氨酸转氨酶(ALT)水平更高(P=0.024),p.Arg778Leu纯合变异和脑型患者相关(P=0.027)。结论:基因检测在WD确诊中发挥重要作用。p.Arg778Leu为中国人群第1高频变异,携带该变异的患者ALT水平较高;p.Arg778Leu纯合变异易导致脑型WD。该研究扩展了ATP7B基因变异谱。

Objective To explore the genotype-phenotype relationship of Wilson's disease(WD)and further study the mutation spectrum in the ATP7B gene.Methods The clinical data and genetic test results of 115 cases with WD diagnosed in the First Affiliated Hospital of Zhengzhou University from 2015 to 2022 were retrospectively analyzed.The rank sum test was used for quantitative data comparison,andχ^(2) test was used for count data comparison.Multivariate logistic regression was used to analyze the relationship between patients'genotype and phenotype.Results The onset of liver manifestations(hepatic type)accounted for 60.9%,neurological symptoms(cerebral type)for 13.0%,and mixed hepato-cerebral symptoms for 26.1%.Presymptomatic individuals(hepatic types)accounted for 62.9%.Next-generation sequencing-diagnosed WD cases accounted for 87.8%.Combined multiplex ligation-dependent probe amplification assay-diagnosed WD cases accounted for 89.6%.A single case with a detected pathogenic locus accounted for 10.4%.The diagnostic rate of WD by genetic testing combined with clinical data was 100%.A total of 76 ATP7B mutations were detected,and the top three mutation frequencies were c.2333G>T(p.Arg778Leu)(30.7%),c.2975C>T(p.Pro992Leu)(7.3%),and c.2621C>T(p.Ala874Val)(6.4%).The mutations were mainly distributed in exons 8,11-13,and 15-18,accounting for more than 90%of the total mutations.Eight new mutations were found,including c.3724G>A(p.Glu1242Lys),c.3703G>C(p.Gly1235Arg),c.3593T>C(p.Val1198Ala),c.2494A>C(p.Lys832Gln),c.1517T>A(p.Ile506Lys),c.484G>T(p.Glu162Ter),c.1870-49A>G,and the missing of exons 10-21.Liver histopathology showed cellular edema,degeneration,inflammation,and necrosis,as well as a 42.8%copper staining positive rate.Genotype-phenotype analysis showed that the p.Arg778Leu mutation had higher alanine aminotransferase(ALT)levels than those carrying other mutations(P=0.024),while the homozygous mutation of p.Arg778Leu was associated with cerebral-type patients(P=0.027).Conclusion Genetic testing plays an important role in the diagnosis of WD.p.Arg778Leu is the first high-frequency mutation in the Chinese population,and patients carrying it have higher ALT levels.The p.Arg778Leu homozygous mutation is prone to causing cerebral-type WD.This study expands the ATP7B gene mutation spectrum.