两例微小额外标记染色体的产前诊断

摘要

目的：探讨两例产前发现的胎儿微小额外标记染色体(small supernumerary marker chromosomes,sSMCs)的起源。方法综合应用外周血染色体 G 显带、C 显带、荧光原位杂交技术(fluorescence in situ hybridization,FISH)、单核苷酸多态性微阵列芯片(single nucleotide polymorphisms array,SNP-array)等技术对2例胎儿微小额外标记染色体进行鉴定。结果病例1羊水核型为47,XY,+mar,Affymetrix CytoScan 750K Array 微阵列芯片扫描结果为 arr 15q11.2q12(22770421-26604587)×4, FISH 验证结果为47,XN,+mar.ish i(15)(q12)(D15Z1+,SNRP N ++,PML -)。病例2羊水核型为46,X,+mar/46,XY,FISH 结果显示该标记染色体为变异的 Y 染色体,两端均有 SRY 信号,FISH 技术验证其核型为46,X,i(Y)(p10)/46,XY。结论在产前诊断中可联合应用多种技术来鉴定胎儿微小额外标记染色体的来源。%Objective To determine the origin of two prenatally detected small supernumerary marker chromosomes (sSMCs ).Methods The sSMCs were analyzed with combined G-banding, C-banding, fluorescence in situ hybridization (FISH ), and single nucleotide polymorphisms array (SNP-array ) techniques.Results In case 1,G-banding analysis has identified a 47,XY,+ mar karyotype.Affymetrix CytoScan 750K Array scan has suggested arr 1 5q1 1.2q12(22 770 421-26 604 587)×4,while FISH analysis suggested 47,XN,+mar.ish i(1 5)(q12)(D1 5Z1 +,SNRP N ++,PML -).In case 2,G-banding analysis has suggested 46,X,+mar/46,XY,FISH analysis showed two SRY hybridization signals,indicating 46,X, i(Y)(p10 )/46,XY.Conclusion Multiple techniques needed be applied for verification of the origin of sSMCs identified in prenatal diagnosis.