Newsletter No. 291

中大通訊 CUHK Newsletter 6 中大通訊 CUHK Newsletter 1. 本刊每月出版兩期，農曆年和暑期停刊。截稿日期載於本刊網頁（ www.cuhk.edu. 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 www.cuhk.edu . hk/iso/newslter/. 2. 來稿請寄沙田香港中文大學資訊處《中大通訊》編輯部（電話2609 8584/2609 8681， 傳真2603 6864，電郵 pub2@uab.cuhk.edu.hk ） 。 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 pub2@uab.cuhk.edu.hk ). 3. 編輯有權刪改及決定是否刊登來稿。 The Editor reserves the right to decline contributions and to edit all articles. 香港中文大學資訊處出版 高級主任：梁素珍 編輯：左冠輝 助理編輯：陳思祥 陳偉珠 製作：梁淑嫻 印刷：璟柏印刷製版有限公司 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 校李嘉誠健康科學研究所所長盧煜明教授率領的 研究組，最近在國際性權威醫學期刊《自然—醫 學》中發表重大研究成果─嶄新唐氏綜合症無創性產 前測試，敏感度高達九成，是現今最準碓的無創性測試 法。該項研究獲香港特別行政區政府創新及科技基金和 李嘉誠基金會「講座教授席」計劃支持。 診斷胎兒有否患上唐氏綜合症是孕婦進行產前檢查的主要 原因。傳統唐氏綜合症測試包括利用超聲波及血液激素測 試，以決定孕婦是否需要繼續進行更詳細及精確的基因檢 測。但是，無論是超聲波或血液激素測試，都不能百分之 百確定胎兒是否患上唐氏綜合症。換句話說，不能直接地 確認第二十一號染色體是否增多了一條。由於這些測檢方 法有機會出現假陽性或假陰性的結果，孕婦須再進行基因 測試。傳統的基因測試，例如羊膜穿刺術（俗稱抽羊胎 水）屬入侵性診斷方法，即是要用針穿過母體進入子宮， 抽取胎兒細胞，會有一定的風險（例如流產）。約每四十 名孕婦進行這些入侵性產前檢查，才有一名確定懷有唐氏 綜合症的胎兒。 盧煜明教授率領的研究組於一九九七年首度發現母體血漿 內有胎兒的脫氧核糖核酸（DNA），為無創性產前診斷 開創了新的研究領域。可是，以母體血漿脫氧核糖核酸 作無創性唐氏綜合症產前測試仍有多種難題未能解決。 盧教授與研究人員利用第二十一號染色體其中一個基因所 表達的核糖核酸（RNA）分子，精密地計算出胎兒由父 親及母親遺傳下來的核糖核酸分子的比例，成功進行無 創性產前唐氏綜合症測試。這項嶄新測試法的敏感度及特 異性分別高達百分之九十及九十六點五，為醫學文獻記載 中最準確的單一無創性唐氏綜合症測試法。理論上，這種 新測試技術已可將傳統的入侵性唐氏綜合症測試減半。目 前這種新測試法仍在研究階段，研究人員會改善現有的技 術，預計未來數年可在臨床上廣泛應用。 李嘉誠健康科學研究所成功地研發的唐氏綜合症新測試 法的優點為： 由母親的血液樣本可直接及無創傷地檢查胎兒有否唐 ·· 氏綜合症； 單一的測試準確度與傳統結合多項測試法的結果相若； ·· 讓更多正常懷孕婦女免卻入侵性的基因檢查； ·· 血液激素測試隨著妊娠周數而改變，但這種無創測試 ·· 法，可於妊娠期內任何時間進行； 新法測試法比傳統的更快有結果，因為部分傳統測試 ·· 需要培植胎兒的細胞組織，時間較長。 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 開拓唐氏綜合症無創性測試新里程 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) 化學病理學系趙慧君教授、婦產科學系劉子建教授、李嘉誠健康科學研究所所長盧煜明教授和化學病理學系博士後研 究員徐寶賢博士 (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