应用Affymetrix SNP Array和FISH技术确认胎儿额外小标记染色体r(4)4p13q13.3

Application of Affymertrix SNP array and FISH analysis in identification of small supernumerary marker chromosome of r(4)4p13q13.3

目的利用AffymetriSNP Array和FISH技术鉴定额外小标记染色体的来源。方法 2013年7月1例38岁高龄孕妇来我院就诊,进行羊水染色体核型分析,G显带检测羊水和脐血胎儿染色体核型,应用AffymetrixCytoScan 750K Array基因芯片技术鉴定额外小标记染色体的片段与来源,然后运用WSH/D4Z1探针的FISH进行确认。结果胎儿羊水G显带染色体核型为46,XX[15]/47,XX,+mar[15],脐血G显带染色体核型为46,XX[14]/47,XX,+mar[16];AffymetrixCytoScan 750K Array基因芯片分析结果为arr 4p13q13.3(41,593,201-72,130,692)X2-3,显示胎儿有4号染色体4p13-着丝粒-q13.3区段30.537 Mb的嵌合性重复;胎儿脐血细胞FISH检测显示28%间期细胞有4号染色体着丝粒的三体性。结论综合应用染色体G-显带核型分析、FISH技术和AffymetrixCytoScan 750K Array芯片技术能准确确认额外微小标记染色体的来源及其片段的界定。

Objective To identify the origin of small supernumerary marker chromosomes （sSMC） by Affymetrix SNP array and FISH analysis. Methods Chromosome karyotype in amniotic fluid and umbilical cord blood from a 38 years old pregnant woman who visited our hospital in July 2013 was detected by G-binding analysis. The fragments and origin of sSMC were identified by AffymetrixCytoScan 750 K array followed by FISH analysis using probe WSH/d4zl. Results G-binding analysis showed a chromosome karyotype of 46, XX[15] /47, XX, ＋mar[15] in amniotic fluid and a chromosome karyotype of 46, XX[14] /47, XX, ＋mar[ 16] in umbilical cord blood. AffymetrixCytoScan 750K array showed a chromosome fragment of arr 4p1 3q 13.3 （41,593,201- 72,130,692）X2-3 in amniotic fluid and a 30.537 Mb long chromosome fragment of 4pl 3-4ql 3.3 with a repeated mosaic in umbilical cord blood. FISH analysis showed that 28% interphase cells in umbilical cord blood displayed a trisomy. Conclusion Combining G banding analysis with FISH analysis and AffymetrixCytoScan 750K array can accurately identify the origin and fragments of sSMC.