产前遗传学诊断胎儿重度侧脑室增宽1例及文献复习

Prenatal genetic diagnosis of severe ventriculomegaly:a case report and literature review

目的报道1例胎儿重度侧脑室增宽的产前遗传学诊断病例,并对相关文献进行复习。方法患者30岁,妊娠32周超声检查发现胎儿重度侧脑室增宽,左侧宽17 mm,右侧宽19 mm,未发现其他异常。之前的产前检查均未发现异常。行脐静脉穿刺术,取脐血细胞行染色体核型分析及单核苷酸多态性微阵列(single nucleotide polymorphism array,SNP array)分析。结果脐血细胞染色体核型分析未见异常。SNP array分析结果为arr9q31.3(113,431,222-113,552,613)x3,14q11.2(20,512,609-22,641,623)x1-2,提示在9q31.3位点存在121 kb的重复,约28%的细胞在14q11.2区段有2.129 Mb片段的缺失,胎儿为该片段缺失的嵌合体。进一步行间期细胞荧光原位杂交(fluorescence in situ hybridization,FISH)分析证实在13%的细胞中存在该位点的缺失,从而验证了SNP array结果的准确性。向孕妇及其家属进行咨询之后,孕妇及家属选择终止妊娠,于妊娠34周行利凡诺引产,分娩一死女婴,孕妇及家属拒绝尸检。结论超声检查发现胎儿孤立性重度侧脑室增宽,应进行产前遗传学诊断。SNP array分析技术是产前诊断新生染色体小片段改变的有效方法,FISH是对嵌合体进行验证的有效手段。

Objective To report a case of prenatal genetic diagnosis for severe ventriculomegaly and to review the literaRres. Methods The woman was 30-year-old. Fetal severe bilateral ventriculomegaly was found by ultrasound at 32 gestational weeks. The width of the left lateral ventricle was 17 mm and that of right was 19 mm. There were no other abnormity to be found by ultrasound. The previous antenatal examination showed nothing abnormal detected. The cordocentesis was performed and cord blood cells were sampled for karyptyping and single nucleotide polymorphism array （SNP array） analysis. Results The karyotype of the cord blood cells showed no abnormal results. The SNP array demonstrated arr 9q31.3（113,431,222-113,552,613）x3,14ql 1.2（20,512,609-22,641,623）xl -2, showing a duplication of 121 kb at 9q31.3 and a deletion of 2.129 Mb at 14q11.2 in 28% of the cells. The partial deletion at 14q11.2 was a mosaieism. Interphase fluoresence in situ hybridization （FISH） demonstrated that the deletion at 14ql 1.2 existed in 13% of the cells, verifying the accuracy of SNP array. After the genetic counseling, the pregnant woman and her family opted to terminate the pregnancy. Induction of labor by rivanol was performed at 34 gestational weeks, and a dead female fetus was delivered, the pregnant woman and her family refused autopsy. Conclusions Genetic diagnosis should be offered to the cases of isolated severe ventriculomegaly detected by ultrasound. SNP array is useful in prenatal diagnosis of de novo alterations of small fragments of the chromosome. FISH is the effective technique to confirm the diagnosis of mosaicism.