一例Xp22.12微重复胎儿的产前诊断及遗传学分析

Prenatal diagnosis and genetic analysis of a fetus with Xp22.12 microduplication

目的:应用单核苷酸多态性微阵列(single nucleotide polymorphism array,SNP-array)技术为1例携带染色体平衡易位的孕妇提供产前诊断。方法:采用常规G显带染色体分析和SNP-array对胎儿及其父母进行分析。结果:SNP-array检测结果显示胎儿染色体Xp22.12区存在496.3 kb的片段重复,临床意义不明;表型正常的母亲染色体Xp22.12区相同位置存在505.8 kb的重复,父亲检测结果未见异常。胎儿足月经剖宫产出生,随访未见异常。结论:Xp22.12微重复区包含RPS6KA3基因的部分区段,因而表现为不同程度的Coffin-Lowry综合征症状,少部分Xp22.12微重复女性可因X染色体失活而成为无症状的携带者,本研究为Xp22.12微重复表型与基因型的关联提供了一定的依据。

Objective To provide prenatal diagnosis for a pregnant women carrying a chromosome translocations using single nucleotide polymorphism array(SNP-array).Methods The fetus and its parents were subjected to chromosome karyotyping and SNP array analysis.Results A Xp22.12 microduplication was identified in the fetus with a size of 496.3 kb.Search of literature and database indicated the microduplication to be variant of unclear significance.The phenotypically normal mother has carried a 505.8 kb duplication at the same position.The father was normal for the testing.The couple decided to continue with the pregnancy and gave birth to a healthy girl at full-term.No abnormality was found during the follow-up.Conclusion The Xp22.12 microduplication encompassed part of RPS6KA3 gene,which shows various features of Coffin-Lowry syndrome.Female with Xp22.12 microduplications may be asymptomatic carriers due to X chromosome inactivation.Our case may provide data for delineating the phenotype-genotype correlation of Xp22.12 microduplication.