【摘要】 目的探讨传统细胞遗传学技术联合SNP-array(single nucleotide polymorphisms array,SNP-array)在识别胎儿微小额外标记染色体(supernumerary marker chromosome,sSMC)致病性中的临床应用价值。方法通过常规G显带技术分析胎儿染色体核型,针对发现的sSMC,应用C显带技术分析sSMC,如果sSMC非异染色质,进一步进行SNP-array辨别其来源并分析相应的表型。结果通过对8575例产前诊断标本G显带核型分析发现4例新发标记染色体,其中C显带示2例为异染色质结构,2例为非异染色质结构。这2例非异染色质结构病例进一步行SNP-array检测,结果示一例未见致病性改变,另一例为4号染色体部分重复。结论 SNP-array能够在基因组水平上识别胎儿sSMC的成分,结合传统的细胞遗传学技术应用于产前诊断中,为确定sSMC的致病性提供了可靠的产前诊断技术平台。更多还原

【Abstract】 Objective: To explore the clinical application of Single Nucleotide Polymorphisms array( SNP-array) and cytogenetic techniques in the prenatal evaluation of fetal with supernumerary small marker chromosome( sSMC). Method: G-banding were perform on all prenatal diagnosis from amniotic fluid and cord blood sample. C banding techniques was used to analyze the sSMC structure. SNP-array was used to analyze the origin and phenotype of the sSMC. Results: In 8575 prenatal diagnostic specimens through the G-banding karyotype detection,4 cases were de novo sSMC. C-banding identify 2 cases as a source of heterochromatin,2 cases were non-source of heterochromatin which were further tested by SNP-array. results shown that one case had no pathogenic genomic change and the other case’s sSMC chromosome comes from the 4th chromosome. Conclusion: SNP-array is an important method to detect the origin of sSMC. Combined with the traditional karyotype analysis in prenatal diagnosis,it provides a valuable prenatal diagnosis technique platform for characterizing the structure of the sSMC.更多还原