一例Wolf-Hirschhorn综合征合并Edward综合征胎儿的遗传学分析

Prenatal genetic analysis of a fetus with Wolf-Hirschhorn syndrome and Edward syndrome

目的对1例无创产前检测18三体高风险、孕28周超声发现心脏畸形、宫内发育迟缓的胎儿进行遗传学分析。方法常规G显带分析胎儿及双亲的染色体核型，应用SNP—array技术对胎儿进行全基因组拷贝数变异（copynumbervariations，CNVs）筛查，分析芯片检出的所有CNVs，并用荧光原位杂交技术（fluorescenceinsituhybridization，FISH）进行验证。结果G显带分析提示胎儿核型为47，XX，＋mar，其父亲染色体核型为46，XY，t（4；18）（p15．2q11．2），母亲核型正常。SNP—array检测胎儿为4p16．3p15．2重复24．7Mb，18p11．32q11．2重复20．5Mb，提示胎儿的标记染色体来源于4p16．3p15，2和18pll_32一q11．2，FISH检测证实其标记染色体遗传自平衡易位的父亲。结论该胎儿被检测出染色体4p16．3p15．2微重复和18p11．32q11．2微重复，因此被诊断为Wolf-Hirschhorn综合征合并Edward综合征。SNP—array可精确定位胎儿标记染色体来源，为产前诊断提供依据。

Objective To screen for genomic copy number variants （CNVs） in a fetus with cardiac abnormalities and intrauterine growth retardation through single nucleotide polymorphism microarray （SNP array） and karyotyping analysis. Methods The fetus and its parents were subjected to conventional G banding and SNP-array analysis. The results were confirmed with fluorescence in situ hybridization （FISH）. Results G-banding analysis showed that the fetus has a karyotype of 47,XX,＋mar. The father has a karyotype of 46, XY, t（4;1 8）（pl 5.2q11.2）, while the mother showed a normal karyotype. SNP array detected two microduplications at 18pll. 32q11.2 （20.5 Mb） and 4p16.3p15.2 （24.7 Mb） in the fetus. The supernumerary marker chromosome carried by the fetus has derived from the balanced translocation carried by its father. The result was confirmed by FISH. Conclusion Based on the two microduplications, the fetus was diagnosed as Wolf-Hirschhorn syndrome in conjunction with Edward syndrome. Verification of the origin of the supernumerary marker chromosome by SNP-array has provided a basis for prenatal genetic diagnosis.