Hunter综合征家系的临床表型、遗传学特征及永生化细胞系的构建  

Clinical phenotype,genetic characteristics,and creation of immortalized cell lines for patients from a pedigree affected with Hunter syndrome

作　　者：李本昌 车凤玉 莫丽党芝 张李钰 王国霞 杨颖[1] Li Benchang;Che Fengyu;Mo Lidangzhi;Zhang Liyu;Wang Guoxia;Yang Ying(Shaanxi Institute for Pediatric Diseases,Xi′an Children′s Hospital,Xi′an,Shaanxi 710003,China)

机构地区：[1]西安市儿童医院、陕西省儿科疾病研究所,西安710003

出　　处：《中华医学遗传学杂志》2024年第8期916-924,共9页Chinese Journal of Medical Genetics

基　　金：陕西省创新能力支撑计划(2019KJXX-055);西安市儿童医院院内课题(2022C03)。

摘　　要：目的探讨1个Hunter综合征家系的临床表型和遗传学特征,并为其构建永生化类淋巴母细胞系。方法选取2022年7月就诊于西安市儿童医院的1例Hunter综合征患儿及其家系成员(2代共6人)作为研究对象。回顾性分析患儿的临床资料,对其进行家系全外显子组测序,对候选变异进行Sanger测序家系验证,并进行生物信息软件分析。通过EB病毒转染构建患儿及其父母的外周血B淋巴细胞永生化细胞系并进行酶活性分析。结果患儿为5岁7月龄男性,表现为手足关节不能伸直、四肢关节大,3月龄出现疝气、舟状头、桶状胸等。患儿的舅舅表现为四肢关节不能伸直、听力差、失明、右侧腹股沟斜疝等。基因检测显示患儿及其舅舅均携带IDS基因(NM_000202.8)c.823G>A(p.D275N)变异。生物信息学分析表明,D275是一个具有高度保守性的位点,D275N变异可能会影响蛋白质空间构象的稳定性,从而降低酶的催化活性。患儿及其父母的永生化类淋巴母细胞系在构建过程中细胞体积增大、呈不规则形状,周围存在毛刺状结构和聚团生长。患儿永生化类淋巴母细胞的IDS酶活值低于检测限。根据美国医学遗传学和基因组学学会(ACMG)相关指南,IDS:c.823G>A(p.D275N)被评级为可能致病变异(PS3+PM2_Supporting+PM5+PP1+PP3)。结论IDS:c.823G>A考虑为该Hunter综合征患儿手足关节不能伸直、四肢关节大的遗传学病因。永生化细胞系的构建为进一步研究上述变异对IDS功能的影响提供了细胞模型。ObjectiveTo explore the clinical phenotype and genetic variant in a Chinese pedigree affected with Hunter syndrome and create immortalized cell lines for the affected pedigree members.MethodsA pedigree of six members who had visited Xi′an Children′s Hospital in July 2022 was selected as the study subject.Clinical data was collected.Whole exome sequencing was carried out for the pedigree members.Candidate variant was verified by Sanger sequencing.In addition,peripheral B lymphocytes were transfected with Epstein-Barr virus to create immortalized cell lines,which were then subjected to enzyme activity analysis.ResultsThe patient,a five-year-and-seven-month-old boy,had exhibited stiff limbs and enlarged joints.He had developed hernia,scaphocephaly,and barrel chest from 3 months of age.His uncle also had stiff limbs,poor hearing,blindness,and right oblique inguinal hernia.Above features had resembled those of Hunter syndrome.Genetic testing revealed that both the child and his uncle had harbored an IDS(NM_000202.8):c.823G>A(p.D275N)variant,which was unreported previously.Bioinformatic analysis indicated that the D275 to be a highly conserved site,and the D275N variant may affect the stability of the protein′s spatial conformation,thereby decrease the catalytic activity of the enzyme.The successfully constructed immortalized lymphoblastoid cell lines for the child and his parents showed increased volume,irregular shape,burr structure and cluster growth.And the value of IDS activity of the patient′s immortalized lymphoblastoid cells was below the limit of detection.Based on the guidelines from the American College of Medical Genetics and Genomics(ACMG),the variant was classified as likely pathogenic(PS3+PM2_Supporting+PM5+PP1+PP3).ConclusionAbove finding has enriched the phenotypic and mutational spectra of Hunter syndrome,and provided a basis for the genetic counseling for this pedigree.The creation of immortalized cell lines has offered a model for further investigation of the impact of variant on the functio

关 键 词：黏多糖贮积症Ⅱ型 HUNTER综合征 IDS基因 永生化类淋巴母细胞 

分 类 号：R725.9[医药卫生—儿科]