Objective: To analyze the potential genetic cause of thrombocytopenia-absent radius (TAR) syndrome in a family and provide prenatal diagnosis for them.
Methods: Genetic mutation analysis of the sporadic family with TAR syndrome was performed with chromosome microarray analysis (CMA), quantitative polymerase chain reaction (qPCR) and Sanger sequencing. DNA samples were collected from 4 members of the family, including the proband, her parents and her sister. CMA, qPCR and Sanger sequencing were performed to determine the pathogenic mutation and prenatal diagnosis of the fetus was made accordingly.
Results: The proband had a 378 kb genomic heterozygous deletion in 1q21.1, which contained RBM8 A and other genes. c.-21G>A mutation was also found in the RBM8 A of the proband. The above-mentioned microdeletion and mutation were inherited from the mother and father, respectively. Prenatal CMA suggested that the fetus carried a 378 kb microdeletion in 1q21.1, and DNA testing did not find c.-21G>A mutation.
Conclusion: The heterozygous deletion in 1q21.1 and RBM8 A: c.-21G>A is considered to be the genetic etiology of TAR syndrome in the family. The study provides information for subsequent family genetic counseling and prenatal diagnosis.
目的: 对一个血小板减少伴桡骨缺失（TAR）综合征家系进行遗传学病因分析及产前诊断。
方法: 采用染色体微阵列分析（CMA）、荧光定量聚合酶链反应（qPCR）和Sanger测序对一个TAR综合征家系进行基因突变分析。提取先证者、父母及姐姐4名家系成员的基因组DNA，行CMA、qPCR和Sanger测序，明确致病突变后对胎儿行产前诊断。
结果: 先证者1q21.1存在378 kb杂合缺失，内含RBM8A等基因，RBM8A基因还存在c.-21G>A突变，上述突变分别遗传自父母。产前羊水CMA显示胎儿1q21.1存在378 kb微缺失，基因检测未见RBM8A基因c.-21G>A突变。
结论: RBM8A基因1q21.1杂合性缺失和c.-21G>A是本例TAR综合征家系的遗传学病因，为本家系的遗传咨询及产前诊断提供了依据。
Keywords: 1q21.1 microdeletion; RBM8A; Thrombocytopenia-absent radius (TAR) syndrome.
Copyright© by Editorial Board of Journal of Sichuan University (Medical Sciences).