两个三指节拇指轴前多指家系的ZRS突变分析  

ZRS mutations in two Chinese Han families featuring triphalangeai thumbs and preaxiai polydactyly

作　　者：赵熙萌 杨威[2] 孙淼[3] 张学[1] 

机构地区：[1]中国医学科学院基础医学研究所北京协和医学院基础学院医学遗传学系,医学分子生物学国家重点实验室,北京100005 [2]首都医科大学附属北京儿童医院,北京100045 [3]苏州大学附属第一医院胎儿医学研究所,215006

出　　处：《中华医学遗传学杂志》2016年第3期281-285,共5页Chinese Journal of Medical Genetics

基　　金：国家自然科学基金（81000783,30871355）;北京市科委行业定额经费资助（2015-bjsekyjs-1）

摘　　要：目的明确两个中国汉族具有三指节拇指特征的轴前多指家系的致病突变。方法知情同意下采集家系1的9名家系成员（患者2例）、家系2的14名家系成员（患者7例）的外周血，提取基因组DNA；应用实时定量PCR与PCR-Sanger测序，对SHH基因的调控元件“极化活性区调控序列”（zone of polarizing activity regulatory sequence，ZRS）分别进行拷贝数与序列突变检测；应用变性聚丙烯酰胺凝胶电泳，检测家系1ZRS附近短串联重复序列的基因型，结合Sanger测序发现的点突变，进行单倍型分析。结果定量PCR显示两家系患者在ZRS区域均不存在拷贝数改变。Sanger测序结果显示，家系1的2例患者均存在ZRS406A〉G杂合突变、家系2的7例患者均存在ZRS105C〉G杂合突变，且突变在各自家系中均与多指表型共分离，在200名正常对照中均未检测到上述突变。已有报道ZRS的105C〉G杂合突变可引起典型的三指节拇指轴前多指；而ZRS的406A〉G杂合突变仅见于1个胫骨发育不良伴多指（趾）家系中。单倍型分析及测序结果提示，家系1中第1例出现肢端畸形的患者为ZRS406A〉G杂合突变的体细胞及生殖细胞嵌合体。结论SHH基因调控元件ZRs的406A〉G与105C〉G杂合突变分别为两个中国汉族三指节拇指轴前多指家系的致病突变。Objective To identify the causative mutations in two Chinese Han families featuring triphalangeal thumbs （TPT） and preaxial polydactyly （PPD）. Methods Blood samples were collected from 9 members （2 affected） from family 1 and 14 members （7 affected） from family 2. After genomic DNA was extracted, the ZPA regulatory sequence （ZRS） region was analyzed with real-time quantitative PCR （qPCR） and Sanger sequencing. For family 1, haplotypes compassing the ZRS were also analyzed with short tandem repeats （STR） and single nucleotide changes. Results No copy number mutation around the ZRS region was found in both families. Two heterogeneous mutations in the ZRS （406A〉G and 105C〉G） were found to co-segregate with the TPT/PPD malformation in family 1 and 2, respectively. Neither mutation was detected in 200 healthy individuals. Haplotype analysis and Sanger sequencing of family 1 indicated that the first TPT/PPD patient in the family （Ⅱ4 ） was both germline and somatic mosaic for the 406A〉G mutation. Conclusion Two pathogenic ZRS mutations, 105C〉G and 406A〉G, have been identified in two Chinese Han families with TPT/PPD, among which the 406A〉G mutation was de novo.

关 键 词：三指节拇指 轴前多指 极化活性区调控序列 点突变 胫骨发育不良伴多指(趾) 

分 类 号：R682[医药卫生—骨科学]