Newsletter No. 291

中大通讯 CUHK Newsletter 6 中大通讯 CUHK Newsletter 1. 本刊每月出版两期,农历年和暑期停刊。截稿日期载于本刊网页( hk/iso/newslter/ )。 The CUHK Newsletter is published on a fortnightly basis except during the Chinese New Year and summer vacation. Deadlines for contribution can be found at . hk/iso/newslter/. 2. 来稿请寄沙田香港中文大学资讯处《中大通讯》编辑部(电话2609 8584/2609 8681, 传真2603 6864,电邮 ) 。 All contributions should be sent to the Editor, CUHK Newsletter , Information Services Office, The Chinese University of Hong Kong (tel. 2609 8584/2609 8681; fax. 2603 6864; e-mail ). 3. 编辑有权删改及决定是否刊登来稿。 The Editor reserves the right to decline contributions and to edit all articles. 香港中文大学资讯处出版 高级主任:梁素珍 编辑:左冠辉 助理编辑:陈思祥 陈伟珠 制作:梁淑娴 印刷:璟柏印刷制版有限公司 Published by the Information Services Office, The Chinese University of Hong Kong Director: Conita S.C. Leung Editor: Chor Koon Fai Assistant Editors: Florence Chan, Piera Chen Production: Pony Leung Printing: Impact Printing & Graphics Co. Ltd. 本 校李嘉诚健康科学研究所所长卢煜明教授率领的 研究组,最近在国际性权威医学期刊《自然—医 学》中发表重大研究成果─崭新唐氏综合症无创性产 前测试,敏感度高达九成,是现今最准碓的无创性测试 法。该项研究获香港特别行政区政府创新及科技基金和 李嘉诚基金会「讲座教授席」计划支持。 诊断胎儿有否患上唐氏综合症是孕妇进行产前检查的主要 原因。传统唐氏综合症测试包括利用超声波及血液激素测 试,以决定孕妇是否需要继续进行更详细及精确的基因检 测。但是,无论是超声波或血液激素测试,都不能百分之 百确定胎儿是否患上唐氏综合症。换句话说,不能直接地 确认第二十一号染色体是否增多了一条。由于这些测检方 法有机会出现假阳性或假阴性的结果,孕妇须再进行基因 测试。传统的基因测试,例如羊膜穿刺术(俗称抽羊胎 水)属入侵性诊断方法,即是要用针穿过母体进入子宫, 抽取胎儿细胞,会有一定的风险(例如流产)。约每四十 名孕妇进行这些入侵性产前检查,才有一名确定怀有唐氏 综合症的胎儿。 卢煜明教授率领的研究组于一九九七年首度发现母体血浆 内有胎儿的脱氧核糖核酸(DNA),为无创性产前诊断 开创了新的研究领域。可是,以母体血浆脱氧核糖核酸 作无创性唐氏综合症产前测试仍有多种难题未能解决。 卢教授与研究人员利用第二十一号染色体其中一个基因所 表达的核糖核酸(RNA)分子,精密地计算出胎儿由父 亲及母亲遗传下来的核糖核酸分子的比例,成功进行无 创性产前唐氏综合症测试。这项崭新测试法的敏感度及特 异性分别高达百分之九十及九十六点五,为医学文献记载 中最准确的单一无创性唐氏综合症测试法。理论上,这种 新测试技术已可将传统的入侵性唐氏综合症测试减半。目 前这种新测试法仍在研究阶段,研究人员会改善现有的技 术,预计未来数年可在临床上广泛应用。 李嘉诚健康科学研究所成功地研发的唐氏综合症新测试 法的优点为: 由母亲的血液样本可直接及无创伤地检查胎儿有否唐 ·· 氏综合症; 单一的测试准确度与传统结合多项测试法的结果相若; ·· 让更多正常怀孕妇女免却入侵性的基因检查; ·· 血液激素测试随着妊娠周数而改变,但这种无创测试 ·· 法,可于妊娠期内任何时间进行; 新法测试法比传统的更快有结果,因为部分传统测试 ·· 需要培植胎儿的细胞组织,时间较长。 A revolutionaryapproach for the noninvasive prenatal testing of Down’s syndrome developed by a team led by Prof. Dennis Lo Yuk-ming from the Li Ka Shing Institute of Health Sciences of the Faculty of Medicine was reported in the latest issue of the top biomedical journal Nature Medicine . This research was supported by the Innovation and Technology Fund of the Hong Kong SAR Government and the Chair Professorship Scheme of the Li Ka Shing Foundation. In 1997, Prof. Lo and his research team discovered for the first time in the world the presence of foetal DNA in the bloodplasma of pregnant women. This discovery has opened up new possibilities 开拓唐氏综合症无创性测试新里程 Breakthrough in Foetal Down’s Syndrome Testing of noninvasive prenatal diagnosis. However, the use of this approach for Down’s syndrome testing has presented a major challenge to many international groups currently working in this field. Prof. Lo’s team has now managed to achieve this previously elusive goal by detecting RNA molecules which are copied from a gene located on chromosome 21. Using a novel approach based on the measurement of the ratio of such RNA molecules copied from gene copies which the foetus has inherited from the father and mother, Prof. Lo and his team have achieved the noninvasive prenatal detection of Down’s syndrome. In cases which can be analysed by this method, the sensitivity and specificity of the test are 90% and 96.5%, respectively. These figures represent the highest yet reported for a single test. While the current, still experimental test can only be used for a proportion of tested cases, this would theoretically half the number of invasive tests needed for Down’s syndrome testing. It is anticipated that with further refinement, this test will be ready for routine utilization in the next few years. The novel Down’s syndrome testing strategy developed by CUHK has the following advantages: • Direct noninvasive detection of fetal Down’s syndrome from a mother’s blood sample • As a stand-alone test, can already achieve similar diagnostic accuracy as the conventional strategy that employs multiple testing components • Can potentially save some normal pregnancies from the need for invasive genetic testing • Unlike the testing of blood hormones, the test profile does not change with the progression of pregnancy. Therefore, a woman can be tested during any time of her pregnancy. • Results can be released in a much shorter time- frame than conventional genetic testing, especially those which are based on fetal cell culture. (左起) 化学病理学系赵慧君教授、妇产科学系刘子建教授、李嘉诚健康科学研究所所长卢煜明教授和化学病理学系博士后研 究员徐宝贤博士 (From left) Prof. Rossa Chiu Wai Kwun of the Department of Chemical Pathology, Prof. Tze Kin Lau of the Department of Obstetrics and Gynaecology, Prof. Dennis Lo Yuk-ming, Director of the Li Ka Shing Institute of Health Sciences, and Dr. Nancy Tsui Bo Yin, postdoctoral fellow of the Department of Chemical Pathology