摘要
目的探讨对原发性纤毛运动障碍(PCD)患儿进行基因检测对指导优生优育的意义。方法对1例临床诊断Kartagener综合征并随访4年的患儿进行家系全外显子组测序(WES),经高通量测序数据分析及临床诊断流程确定致病基因突变,根据基因诊断结果行针对性遗传咨询后对患儿母亲第2胎行羊水穿刺,分离羊水脱落细胞,提取基因组DNA并PCR扩增羊水脱落细胞相应基因突变所在外显子,行直接Sanger测序。结果临床随访发现患儿肺功能较诊断时明显下降,胸部CT支气管扩张较前加重。WES患儿中检测到CCDC39基因c.1819A>A/T,p.K607X无义突变和c.2447_2448het_del CA,p.T816Kfs*3移码突变,2个突变均为未报道的新突变,均经功能预测工具Mutation Taster预测为致病突变,分析父母突变来源确定为复合杂合突变。同时结合患儿支气管黏膜活检电镜特征性的纤毛结构异常,认定该复合杂合突变为患儿的致病突变。患儿母亲第2胎羊水细胞CCDC39基因2个突变位点所在外显子的Sanger测序结果显示,胎儿携带母亲来源的移码突变,无父亲的无义突变,为单杂合突变携带者。结论采用WES检测有助于明确PCD患儿的遗传病因,在此基础上对患儿家庭行遗传咨询和产前基因诊断,可以指导优生优育。
Objective To identify the genetic defect in a child with primary ciliary dyskinesia and provide genetic counseling and prenatal diagnosis for the family.Methods Whole exome sequencing（WES） was performed in a case with a clinical diagnosis of Kartagener syndrome as well as her asymptomatic parents.The data analysis pipeline of Children＇s Hospital of Fudan University was used to identify pathogenic mutations.Amniocentesis was conducted for the mother in her second pregnancy after a thorough genetic counseling.Genomic DNA was extracted from exfoliated amniotic fluid cells and Sanger sequencing was performed after PCR amplification.Results During follow-ups,the lung function of the patient deteriorated markedly and bronchiectasis shown in chest CT was aggravated.A heterozygous nonsense mutation（c.1819 A 〉A / T,p.K607X） and a frameshift mutation（c.2447_2448het_del CA,p.T816Kfs＊ 3） in CCDC39 gene were detected in this patient by WES.Both mutations were novel and predicted to be disease-causing.Mutational analysis of the parents demonstrated they were compound heterozygous mutations.These compound heterozygous mutations were consistent with ciliary structural abnormity revealed by electron microscope thus suggesting the pathogenic nature of these mutations.Sequencing of the amniotic fluid cells showed that the fetus only carried one heterozygous mutation which was inherited from the mother.Conclusion The compound heterozygous mutations in CCDC39 gene detected by WES was the genetic cause of primary ciliary dyskinesia.Genetic counseling and prenatal diagnosis may be helpful to the family based on the basis of this genetic diagnosis.
出处
《中国循证儿科杂志》
CSCD
北大核心
2016年第6期445-449,共5页
Chinese Journal of Evidence Based Pediatrics
基金
上海市科委西医引导项目:134119a7800
14411962102
上海市人才发展基金:沪人201450
