一个希特林缺陷病家系SLC25A13基因的新剪接位点变异及异常转录子

A novel SLC25A13 variant and the resultant aberrant transcript identified in a pedigree affected with citrin deficiency

目的 探讨1例希特林缺陷病患儿的临床及遗传学特征。 方法 整理分析患儿临床资料,提取患儿及其父母外周血DNA标本,采用靶向外显子测序检测致病突变,并通过一代测序进行验证。提取患儿外周血淋巴细胞mRNA,通过逆转录-PCR、cDNA克隆和Sanger测序等技术,分析新突变对SLC25A13转录产物的影响。 结果 患儿为SLC25A13突变c.845_c.848+1delG和c.1841+3_1841+4delAA复合杂合子,后一突变尚未见文献报道,克隆结果证实该突变造成mRNA异常剪接,形成异常转录子[r.1841_1842ins1841+1_1841+67;1841+3_c.1841+4del]。 结论 本研究通过传统DNA分析方法结合cDNA克隆技术,发现了新突变c.1841+3_1841+4delAA及其异常剪接变异体,为患儿希特林缺陷病确诊提供了实验依据,同时扩展了SLC25A13基因突变谱。

Objective To explore the clinical and genetic features of an infant with citrin deficiency (CD).Methods Clinical data of the patient was collected and analyzed. Genomic DNA was extracted from peripheral blood samples collected from the patient and her parents. Targeted exome sequencing was performed to explore the genetic cause, and Sanger sequencing was used to confirm the detected variants. SLC25A13 mRNA was extracted from peripheral blood lymphocytes of the infant. The effect of novel mutation of SLC25A13 was analyzed by reverse transcription-PCR, cDNA cloning and Sanger sequencing.Results The SLC25A13 genotype of the patient was determined as c. 845_c.848+ 1delG/c.1841+ 3_1841+ 4delAA, with the latter having not been reported. The mutation has affected the splicing of the SLC25A13 mRNA, giving rise to an aberrant transcript [r.1841_1842ins1841+ 1_1841+ 67;1841+ 3_c.1841+ 4del]. Conclusion A novel SLC25A13 mutation c. 1841+ 3_1841+ 4delAA and the resultant abnormal splicing variant were discovered by combined DNA sequencing and cDNA cloning. The finding has enabled definite diagnosis of CD and enriched the spectrum of SLC25A13 mutations.