Smart R D, Retief A E, Overhauser J
Department of Human Genetics, Medical School, University of Cape Town, South Africa.
Prenat Diagn. 1989 Jul;9(7):505-13. doi: 10.1002/pd.1970090708.
Investigation of a couple, who had produced three babies with cri du chat syndrome, showed initially that the mother had an apparent deletion of chromosome 5. It seemed likely that she had a balanced chromosomal translocation but it proved impossible to detect the second chromosome involved using routine cytogenetic methods. Molecular techniques using quantitative hybridization dosage studies were performed and these showed that the mother had a double dose of DNA in the suspected deleted area of chromosome 5. Further studies, using in situ hybridization techniques, revealed that the missing segment of chromosome 5 had translocated onto the short arms of a C group chromosome and further analysis of prometaphase chromosomes showed the presence of a balanced translocation, 46,XY,t(5;9)(5qter----5p14.1::9p22----9pter;9 qter----9p22::5p14.1----5pter). As a result of these findings, it was possible to offer prenatal diagnosis to the patient in future pregnancies, by detecting the presence of a balanced or unbalanced translocation in the fetus using molecular and cytogenetic techniques.
对一对育有三名患有猫叫综合征婴儿的夫妇进行调查，最初发现母亲的5号染色体存在明显缺失。她似乎有一条平衡的染色体易位，但事实证明，使用常规细胞遗传学方法无法检测出涉及的第二条染色体。进行了使用定量杂交剂量研究的分子技术，结果显示母亲在5号染色体的疑似缺失区域有双倍剂量的DNA。使用原位杂交技术的进一步研究表明，5号染色体缺失的片段已易位到C组染色体的短臂上，对早中期染色体的进一步分析显示存在平衡易位，核型为46,XY,t(5;9)(5qter→5p14.1::9p22→9pter;9 qter→9p22::5p14.1→5pter)。基于这些发现，未来有可能通过分子和细胞遗传学技术检测胎儿中平衡或不平衡易位的存在，为该患者未来的妊娠提供产前诊断。
