一个Ⅲ型家族性噬血细胞组织细胞增生症家系的临床及基因变异分析  

Analysis of clinical phenotype and genetic variant in a case of familial hemophagocytic lymphohistiocytosis type Ⅲ

作　　者：王越[1] 罗强 田培超[1] 刘玉峰[1] 王怀立[1] Wang Yue;Luo Qiang;Tian Peichao;Liu Yufeng;Wang Huaili(Department of Pediatrics,the First Affiliated Hospital of Zhengzhou University,Zhengzhou,Henan 450052,China)

机构地区：[1]郑州大学第一附属医院儿科,郑州450052

出　　处：《中华医学遗传学杂志》2022年第6期616-620,共5页Chinese Journal of Medical Genetics

摘　　要：目的探讨一例Ⅲ型家族性噬血细胞综合征(familial hemophagocytic lymphohistiocytosis typeⅢ,FHL-3)家系的致病变异及临床特点。方法对1例确诊为FHL-3的患儿及其家系成员进行回顾性分析,通过家系全外显子及相邻内含子测序对先证者进行筛查,并对候选变异进行Sanger测序验证。以健康对照和患者的基因组DNA为模板,构建包含UNC13D基因第23外显子、第23内含子和第24外显子的野生型和变异型minigene真核表达质粒。采用脂质体法用携带minigene的质粒转染HEK293T细胞,通过实时定量PCR检测minigene的剪接情况。结果家系分析和临床诊断提示先证者患有常染色体隐性遗传的FHL-3。测序发现其UNC13D基因存在c.118-308(IVS1)C>T和c.2298+1(IVS23)G>A变异,经Sanger测序验证分别来自父亲和母亲,构成复合杂合变异,判断为致病性。Minigene实验证实UNC13D基因c.2298+1(IVS23)G>A变异可导致第23外显子跳跃(-207nt),产生截短蛋白。结论UNC13D基因c.118-308(IVS1)C>T和c.2298+1(IVS23)G>A可能是该FHL-3家系的致病变异,可导致UNC13D mRNA低表达和pre-mRNA的异常剪接。Objective To explore the genetic basis for a newborn with familial hemophagocytic lymphohistiocytosis type 3(FHL3).Methods Clinical and laboratory data of the newborn and his family members were reviewed.Whole exome sequencing(including and flanking intronic regions)was carried out.Candidate variants were verified by Sanger sequencing.Wild type and mutant minigene vectors containing exon 23,intron 23 and exon 24 of the UNC13D gene were constructed and transfected into HEK293T cells by lipofectamine reagent.Reverse transcription PCR was carried out to verify the splicing of the minigenes.Results Pedigree analysis and clinical examinations indicated that the child has autosomal recessive FHL3.DNA sequencing revealed that he has harbored c.118-308(IVS1)C>T and c.2298+1(IVS23)G>A variants of the UNC13D gene,which were respectively inherited from his father and mother,which constituted compound heterozygosity and were both predicted to be pathogenic.Minigene experiment confirmed that the c.2298+1(IVS23)G>A variant has resulted skipping of exon 23(-207nt)resulting in a truncated protein.Conclusion The c.118-308(IVS1)C>T and c.2298+1(IVS23)G>A compound heterozygous variants of the UNC13D gene probably underlay the FHL3 in this child,which has resulted in low expression as well as abnormal splicing of UNC13D mRNA.

关 键 词：家族性噬血细胞综合征Ⅲ型 UNC13D基因 内含子变异 剪接变异 

分 类 号：R725.9[医药卫生—儿科]