[Phenotypes and ATP7B gene variants in 316 children with Wilson disease].

Objectives: To summarize the clinical phenotypes and the variation spectrum of ATP7B gene in Chinese children with Wilson's disease (WD) and to investigate their significance for early diagnosis. Methods: Retrospective analysis was performed on the clinical data of 316 children diagnosed as WD in Guangzhou Women and Children's Medical Center during the period from January 2010 to June 2021. The general situations, clinical manifestations, lab test results, imaging examinations, and ATP7B gene variant characteristics were collected. The patients were divided into asymptomatic WD group and symptomatic WD group based on the presence or absence of clinical symptoms at the time that WD diagnosis was made. The χ2 test, t test or Mann-Whitney U test were used to compare the differences between groups. Results: Among the 316 children with WD, 199 were males and 117 were females, with the age of 5.4 (4.0, 7.6) years at diagnosis; 261 cases (82.6%) were asymptomatic with the age of 4.9 (3.9, 6.4) years; whereas 55 cases (17.4%) were symptomatic with the age of 9.6 (7.3, 12.0) years. The main symptoms invloved liver, kidney, nervous system, or skin damage. Of all the patients, 95.9% (303/316) had abnormal liver function at diagnosis; 98.1% (310/316) had the serum ceruloplasmin lever lower than 200 mg/L; 97.7% (302/309) had 24-hour urine copper content exceeding 40 μg; only 7.4% (23/310) had positive corneal K-F rings, 8.2% (23/281) had abnormal MRI signals in the lenticular nucleus, and all of them had symptoms of damage in liver, kidney or nervous system. Compared with the group of symptomatic WD, asymptomatic group had higher levels of serum alanine aminotransferase and lower levels ceruloplasmin and 24-hour urine copper [(208±137) vs. (72±78) U/L, (55±47) vs. (69±48) mg/L, 103 (72, 153) vs. 492 (230, 1 432) μg; t=9.98, -1.98, Z=-4.89, all P<0.001]. Among the 314 patients completing genetic sequencing, a total of 107 mutations in ATP7B gene were detected, of which 10 are novel variants, and 3 cases (1.0%) had large heterozygous deletion (exons 10 to exon 11) in ATP7B gene. The percentage of missense mutation in asymptomatic WD children was significantly higher than that in symptomatic WD (81.5% (422/518) vs. 69.1% (76/110), χ²=8.47, P<0.05). WD patients carrying homozygous variant of c.2 333G>T had significantly low levels of ceruloplasmin than those not carrying this variant ((23±5) vs. (61±48) mg/L, t=-2.34, P<0.001). Conclusions: The elevation of serum ALT is an important clue for early diagnosis of WD in children, while serum ceruloplasmin and 24-hour urine copper content are specific markers for early diagnosis of WD. In order to confirm the diagnosis of WD, it is necessary to combine the Sanger sequencing with multiplex ligation-dependent probe amplification or other testing technologies.目的： 总结儿童肝豆状核变性（WD）的临床表型及ATP7B基因变异类型特征，探讨其对WD早期诊断的临床意义。 方法： 回顾性分析2010年1月至2021年6月就诊于广州市妇女儿童医疗中心的316例WD患儿的临床资料。收集患儿一般情况、临床表现、实验室检查、影像学检查、ATP7B基因变异特征等资料。根据诊断时有无临床症状分为无症状组和有症状组，组间比较采用χ²检验、t检验或Mann-Whitney U检验。 结果： 316例WD患儿中男199例、女117例，确诊年龄为5.4（4.0，7.6）岁。无症状组261例（82.6%），年龄4.9（3.9，6.4）岁；有症状组55例（17.4%），年龄9.6（7.3，12.0）岁，主要症状为肝肾功能、神经和皮肤损伤。所有WD患儿中，95.9%（303/316）确诊时肝功能异常；98.1%（310/316）血清铜蓝蛋白低于200 mg/L；97.7%（302/309）24 h尿铜含量超过40 μg；仅7.4%（23/310）角膜K-F环阳性和8.2%（23/281）头颅磁共振成像提示豆状核异常信号，且均有肝肾功能或神经损伤等症状。无症状组WD患儿血清丙氨酸转氨酶（ALT）水平高于有症状组，铜蓝蛋白和24 h尿铜含量均低于有症状组［（208±137）比（72±78）U/L，（55±47）比（69±48）mg/L，103（72，153）比492（230，1432）μg，t=9.98、-1.98、Z=-4.89，均P<0.001］。314例患儿完成ATP7B基因检测，共检测到107种变异类型，其中10种新发变异，检测到3例患儿携带第10~11号外显子杂合缺失。无症状组患儿携带错义变异的比例显著高于有症状组［81.5%（422/518）比69.1%（76/110），χ²=8.47，P<0.05］。携带c.2333G>T纯合变异的WD患儿（106例）的血清铜蓝蛋白水平显著低于不携带者（208例）［（23±5）比（61±48）mg/L，t=-2.34，P<0.001］。 结论： ALT升高是儿童WD早期诊断的重要线索，而血清铜蓝蛋白和24 h尿铜含量是儿童WD早期诊断的特异性指标。需结合Sanger测序和多重连接依赖探针扩增技术等多种检测技术明确WD的基因诊断。.