摘要
15%-20%的妊娠因为自发流产而中止,其中约50%是因为染色体异常所致。夫妇中的一方为平衡的染色体异常携带者时,即可能产生不平衡的配子和胚胎,临床症状可以有不同程度的变化:如不育、反复流产、甚至产出染色体综合症的患儿。以临床接诊的一对具有反复自然流产史夫妇为研究对象,常规进行精液、激素水平检测。取患者外周血淋巴细胞用RPMI1640培养基进行短期培养,经低渗、固定处理制备染色体标本片,对染色体数目和结构进行核型分析。选用特异的21qter和14qterDNA标记作为探针,对患者外周血淋巴细胞中期染色体进行FISH分析。运用FISH技术对患者精子细胞进行研究,配合流式细胞分析技术对精细胞DNA组份进行检测,分析配子中遗传物质的组成及各种类型配子的比例。结果发现女方核型正常为46,XX,男方核型为罗伯逊易位的携带者45,XY,-14,-21,+t(14;21)。患者外周血体细胞的分裂相染色体FISH显示一个细胞中分别存在1个红色的21qter和1个绿色的14qter杂交信号,另外有1个红色和1个绿色信号共同存在于一条由易位形成的亚中着丝粒染色体上。在患者精液样本的精细胞FISH研究中,可以观察到5种不同类型的杂交信号,异常的配子的种类与理论推断相同,但各型所占的比例有其特点,结合精液中精细胞流式细胞术的分析表明,平衡的单倍体配子占71%,不平衡的配子占29%。通过国内外文献资料统计,对罗伯逊易位染色体的常见和罕见类型进行综述,为其生育的临床治疗方案提供建议。
Approximately 15%-20% of clinically recognizable pregnancies end in spontaneous abortion. About half of the spontaneous abortions in the early stage of the pregnancy are due to chromosomal abnormalities. Using GTG chromosome banding and dual-color fluorescence in situ hybridization （FISH） techniques, we determined the cytogenetic aberration in the husband of a couple with spontaneous recurrent abortions. Karyotype analysis showed 46, XX in the wife and 45, XY, -14, -21, ＋t（14; 21） in the husband.We studied the mechanism of formation of the abnormal chromosome with Robertsonian translocation between chromosomes 14 and 21 by FISH and flow cytometric sorting in the sperm cells. The result showed that 71% of the gametes were balanced and the remaining 29% were not. As a result, the couple was given genetic counseling.
基金
This work was supported by the 10th Five Years Program for Science and Technology Development of China (No.2004BA720A33-01).
