羊水衍生X染色体的细胞与分子遗传学分析

目的 对1例孕中期胎儿46,X,der(X)行细胞与分子遗传学研究,并探讨其临床效应.方法 采用羊水细胞培养和G、C显带技术制备染色体,应用X染色体计数探针、Y染色体计数探针、Tel Xp/Yp三色荧光原位杂交技术(fluorescence in situ hybridization,FISH)进一步分析确定其核型.结果 衍生染色体为罕见的X/Y染色体的易位,其核型为:46,X,der(X)t(X;Y)(p22.3;q11.2).ish der(X)t(X;Y)(p22.3;q11.2)(X/Ypter-,DXZ1+,DYZ1+)mat.结论 FISH结合细胞遗传学检测可以查明衍生染色体的来源和性质,从而为产前诊断提供更全面准确的遗传学依据,并能预测胎儿发生畸形的风险及准确地判断预后.

Conventional and molecular cytogenetic analyses of a derivative X chromosome in amniocentesis

Objective To analyze the aberrant der(X) chromosome using conventional and molecular cytogenetic approaches in a fetus of second trimester and to discuss its clinical effect. Methods Conventional cytogenetic procedures (GTG and CBG banding) were performed on cultured amniotic fluid cells. Threecolor fluorescence in situ hybridization (FISH) consisting of X chromosome enumeration probes(CEPX),CEPY and Tel Xp/Yp was further performed to study the aberrant der(X) chromosome. Results Der(X)was a rare X/Y translocation. The final karyotypes of the fetus was designated as: 46, X, der (X) t (X ; Y)(p22.3;q11. 2).ishder(X)t(X;Y)(p22.3;q11. 2)(X/Ypter-, DXZ1+, DYZ1+)mat. Conclusion The combination of FISH and conventional cytogenetic techniques is a powerful tool to determine derivative chromosome and to offer an accurate genetic counseling. Identification of Xp; Yq rearrangement can help estimate the risk of fetus abnormalities and give a more precise prognosis.