Scribble基因体细胞突变与神经管缺陷的关联研究

Association of somatic mutations in Scribble gene with neural tube defects

目的筛选中枢神经系统病变组织中神经管缺陷(NTDs)发病相关的Scribble(SCRIB)基因的突变位点,并探讨突变来源,鉴定其是否为体细胞突变。方法用Ion Personal Genome Machine(PGM)测序技术检测28例NTDs患儿病变处和脐带组织DNA,筛选体细胞突变位点,并用Sanger测序对病变处和脐带、皮肤、心脏、肌肉、胸腺和肺组织DNA进行测序。进一步扩大样本量(51例病例)验证已发现突变。结果对28名NTDs患儿进行PGM测序,在1例患儿病变处检测到c.1931G>C突变;另1例患儿病变处检测到c.1265C>T突变;在该2名患儿脐带组织中未检测到相应的突变,提示c.1931G>C和c.1265C>T为体细胞突变。其中1名患儿用Sanger法测序在皮肤、心脏、肌肉、胸腺和肺组织均检测到c.1931G>C突变;另1名患儿的各非病变组织均未检测到c.1265C>T突变。扩大样本量研究没有检测到c.1931G>C突变;在5名患儿的病变处及各非病变组织中均检测到c.1265C>T多态性变异,提示此突变在这5名患者中可能来源于父母。结论 NTDs的发生不仅与SCRIB基因来源于父母的突变有关,还与体细胞突变有关,体细胞突变理论可为NTDs发生的遗传机制提供新的思路。

Objective To screen mutations in SCRIB gene associated with neural tube defects （NTDs） in lesion tissue of the central nervous system,explore the source of mutations,and to identify whether they are somatic mutations.Methods DNA from the lesion and umbilical cord tissues of 28 fetuses/newborns with NTDs was sequenced by Ion Personal Genome Machine （PGM） and to screen somatic mutations.Sanger sequencing was used to detect the mutations in lesion,umbilical cord,skin,heart,muscle,thymus and lung tissue.Validation in an independent sample set of 51 NTDs cases were performed.Results In all 28 NTDs cases,mutation of c.1931G 〉 C was detected in the lesion tissue in one case and c.1265C 〉 T was detected in another case through PGM sequencing;no mutations were detected in the umbilical cord tissue of corresponding cases,suggesting that c.1931G 〉 C and c.1265C 〉 T were somatic mutations.Mutation of c.1931G 〉 C was detected in the skin,heart,muscle,thymus,and lung tissues in the case carrying the mutation;while mutation of C.1265C 〉 T mutation was not detected in any tissues in the case carrying the mutation.The c.1931G 〉 C mutation was not detected in the expanded sample,while c.1265C 〉 T polymorphism was detected in the lesion and non-lesion tissues in 5 cases.Conclusion The mutations of SCRIB gene were associated with the occurrence of NTDs.The mutations may be inherited from parents,but also may be resulted from somatic mutation.Our study shed some light on the genetic mechanisms of NTDs development.