Jin Xiaoxiao, Jin Pengzhen, Yan Kai, Qian Yeqing, Dong Minyue
Department of Reproductive Genetics, Women's Hospital, Zhejiang University School of Medicine, Key Laboratory of Reproductive Genetics, Ministry of Education, Hangzhou 310006, China.
Zhejiang Da Xue Xue Bao Yi Xue Ban. 2020 Oct 25;49(5):586-590. doi: 10.3785/j.issn.1008-9292.2020.10.06.
To perform gene mutation analysis in a patient with atypical clinical manifestations of tuberous sclerosis (TSC) for definite diagnosis.
Peripheral blood DNA was obtained from a patient with clinically suspected TSC and her parents, and all exons and their flanking sequences of and genes in the proband were sequenced by whole exome sequencing to determine the candidate pathogenic mutations. At the same time, Sanger sequencing was performed to verify the peripheral blood DNA of the patient and her parents. And the mosaic percentage of the mutation in the proband's somatic cells was detected by the droplet digital PCR method.
A heterozygous nonsense mutation c.1096G>T (p.E366*) was identified in the exon 11 of the gene, which only had a small mutation peak. A lower percentage of the mutation was found in the DNA of the patient than that in the public database, therefore the possibility of mosaicism might not be excluded. In addition, the droplet digital PCR method demonstrated that the proband was a c.1096G>T mutant mosaicism, and the mosaic percentage was 14%.
The somatic mosaic mutation c.1096G>T (p.e366*) may be responsible for the phenotype of TSC in this patient. And the drop digital PCR is expected to be a diagnostic method for somatic cells mosaicism.
对一名具有结节性硬化症（TSC）非典型临床表现的患者进行基因突变分析以明确诊断。
从一名临床疑似TSC的患者及其父母获取外周血DNA，通过全外显子测序对先证者的 和 基因的所有外显子及其侧翼序列进行测序以确定候选致病突变。同时，采用桑格测序法验证患者及其父母的外周血DNA。并通过液滴数字PCR法检测先证者体细胞中突变的镶嵌比例。
在 基因第11外显子中鉴定出一个杂合无义突变c.1096G>T（p.E366*），其仅有一个小的突变峰。在患者DNA中发现的该突变比例低于公共数据库中的比例，因此不能排除镶嵌现象的可能性。此外，液滴数字PCR法表明先证者为c.1096G>T突变镶嵌体，镶嵌比例为14%。
体细胞镶嵌突变c.1096G>T（p.e366*）可能是该患者TSC表型的原因。液滴数字PCR有望成为体细胞镶嵌现象的诊断方法。
