基于二代测序技术的产前诊断X染色体短臂缺失的遗传学分析

Prenatal genetic analysis for X chromosome short arm deletion using second-generation sequencing

目的 对Xp22->pter缺失病例进行产前诊断,并探讨其临床特征及遗传学特点,为遗传咨询提供帮助。方法 采用染色体核型分析、基因组拷贝数变异测序技术诊断X染色体结构异常。结果 核型分析结果显示胎儿及其母亲均为46,X,del(X)(p22.1),低深度高通量全基因组测序结果显示胎儿Xp22.11~p22.33存在24.59Mb缺失,母亲Xp22.11~p22.33有24.63Mb缺失。结论 联合分子遗传及细胞遗传技术可以对X染色体短臂缺失进行更精确的诊断。X短臂缺失临床表现虽具有遗传异质性,但普遍具有身材矮小的表现。该病例母亲除表现为身材矮小外,还有乳腺纤维瘤病史。

Objective To provide better means of assessment and prenatal counseling for cases with X chromosome short arm deletions,we explored the clinical and genetic characteristics of carriers of Xp22->pter deletions.Methods Karyotype analysis and CNV-seq were used to diagnose X chromosome structural abnormalities.Results The karyotype analysis results of the fetus and mother were as follows:46,X,del(X)(p22.1).CNV-seq showed that a 24.59 Mb region was deleted from the fetal chromosome X at p22.11-p22.33,and a 24.63 Mb region was deleted from the mother's chromosome X at p22.11-p22.33.Conclusion In prenatal diagnosis,the combined application of karyotype analysis and CNV-seq is helpful in making a more accurate diagnosis of X short arm deletion.Although the phenotype of X short arm deficiency has genetic heterogeneity,it is mainly associated with short stature.In addition to presenting with short stature,the mother of this case also hasahistoryofbreastfibroma.