生育大事件:準(zhǔn)媽媽滴血可查胎兒基因
????投資銀行Poliwogg的醫(yī)療戰(zhàn)略分析師雷斯?范特雷德認(rèn)為:“至于這種產(chǎn)前基因檢測技術(shù)是否會成為一種標(biāo)準(zhǔn),它肯定是可能的,但是首先他們要把價格降到比現(xiàn)在更低的水平,。那些托管型醫(yī)療保健公司不會一窩蜂地沖到新領(lǐng)域上去花錢,。如果開發(fā)這種技術(shù)的公司能夠證明它確實能提高醫(yī)療服務(wù)質(zhì)量或降低成本,那么它可能會成為標(biāo)準(zhǔn)醫(yī)療保健的一部分,。但是如果它反而增加了懷孕的成本,,它肯定不會受到人們的熱烈歡迎?!?/p> ????NIPT公司們也正在努力攻克這個問題,。過去一兩年里,這項技術(shù)已經(jīng)取得了巨大的進(jìn)步,。2011年以來,,好幾家公司都推出了商業(yè)化的測試手段(有些從親子鑒定開始,特別是早在懷孕8周的時候,,就可以鑒定出胎兒是不是準(zhǔn)爸爸的親生兒子),。之后這些公司又在測試中加入了許多新的診斷目標(biāo),現(xiàn)在它已經(jīng)可以檢測包括唐氏綜合癥等基因病,、各種不易被發(fā)現(xiàn)的綜合癥,,以及各種性染色體異常。其中有些基因病在少兒時代很難檢測出來,,往往等到確診之后再對孩子進(jìn)行激素治療已經(jīng)為時太晚,。未來這種NIPT技術(shù)還可以用來檢測囊細(xì)胞纖維癥、薩氏病,、鐮狀細(xì)胞性貧血,甚至能檢測出與常見癌癥有關(guān)的基因,。由于這種測試只是簡單地從母親的血樣中提取胎兒的基因信息,,因此NIPT能檢測出的基因病和遺傳指標(biāo)的數(shù)量,最終將只是局限于醫(yī)生對某一類基因的理解,。 ????作為一項診斷工具,,目前大部分接受這項測試的人都是所謂的高風(fēng)險群體——一般來說指的是35歲以上的孕婦(因為高齡產(chǎn)婦的胎兒更易患唐氏綜合癥),或者是其他存在已知染色體病變風(fēng)險的人群,。不過,,Natera和Verinata等公司目前都在設(shè)計用于一般人群的NIPT試驗,以證明這種技術(shù)同樣適用于非高風(fēng)險孕婦的胎兒的基因篩查,。由于非高風(fēng)險孕婦的比例遠(yuǎn)遠(yuǎn)高于高風(fēng)險人群,,因此一旦這種試驗獲得了成功,它可能會成為所有懷孕的準(zhǔn)媽媽們都會選擇的標(biāo)準(zhǔn)測試,,變成像超聲波檢查一樣常規(guī)的檢查,。 ????Natera公司的CEO馬特?拉比諾維茨博士表示,如果情況真的朝著這個方向方展,背后的推動因素也并不是唐氏綜合癥或性染色體異常等問題,,而是NIPT的下一個戰(zhàn)場——缺失癥候群,。缺失癥候群是指一個染色體的部分或全部由于各種原因從基因中缺失了,進(jìn)而導(dǎo)致嬰兒發(fā)育期的各種生理問題,。人們未必非常了解這些癥候群,,但是醫(yī)生們知道它們的確存在,而且從事NIPT的公司也非常自信地認(rèn)為,,他們能夠檢測到這些癥候群,。具有這種功能的商業(yè)化檢測產(chǎn)品在未來6到18個月里就會面世。 ????拉比諾維茨說:“我非??隙?,它將會成為涵蓋整個人口的一個前沿性測試。而使它覆蓋整個人口的推動力就是缺失癥候群,。我們非常想檢測出這些癥候群,,如果能把這種篩查測試擴大到整個人口的范圍,這將是一件非常了不起的事,?!?/p> ????拉比諾維茨還說,如果NIPT在整個人口范圍內(nèi)得到采用,,它將對醫(yī)療事業(yè)產(chǎn)生巨大的影響,。并不是只有他一個人這么想。NIPT測試本身只提取了胎兒的基因信息,,因此唯一能限制其檢測功用的就是醫(yī)生對這些基因的臨床理解,。醫(yī)生可以利用檢測結(jié)果制定治療方法,做出臨床決策,。而且根據(jù)摩爾定律,,這門篩查技術(shù)的潛在用途還在以驚人的速度增長。 ????,。 |
????"Whether or not prenatal genetic testing becomes standard, it's certainly possible, but they're going to have to get the price point down lower than it is right now," says Les Funtleyder, a health care strategist at investment firm Poliwogg. "Managed care companies aren't rushing toward new places to spend money. If the companies in question can make the case that by doing this you're somehow improving quality or cutting costs, they could become part of standard care. But if they're adding cost onto the price of pregnancy, it won't be received enthusiastically." ????That's the case the companies in this space are working to make right now. Over the past couple of years the technology has matured tremendously, with several firms bringing commercial tests to market since 2011 (a few started as paternity tests, significant in that they could determine paternity as early as eight weeks into a pregnancy). Since then, those companies have moved quickly to pile new diagnostic targets into those tests, which now screen for everything from chromosomal disorders like Down and a number of other less-notable syndromes to various sex chromosome abnormalities, many of which go undetected in young children until they are too old for hormone treatments to be effective. In the future these same NIPT diagnostics could screen for cystic fibrosis, Tay-Sachs, sickle cell anemia, and even the presence of certain genes associated with common cancers. Because the tests themselves simply extract the genetic information from the mother's blood sample, the number of disorders and genetic indicators NIPT could eventually test for is really only limited by doctors' understanding of the genome. ????Yet as a diagnostic tool, these tests have largely been relegated to what are considered high-risk populations -- typically pregnant women 35 or older (for Down syndrome) or that carry some other known risk for a chromosomal disorder. But both Natera and Verinata are designing and conducting general population trials to prove their efficacy in spotting chromosomal and genetic issues in the unborn children of non-high-risk mothers -- a proposition that, if proven, could accelerate the adoption of NIPT across the board as a standard test for all pregnant mothers, something as routine as ultrasound. ????The impetus for this won't be Down Syndrome or sex chromosome abnormalities, says Natera CEO Dr. Matt Rabinowitz, but NIPT's next frontier, so-called deletion syndromes. These occur when all or part of a chromosome, for whatever reason, is deleted from the genome, causing various developmental problems for the child. These syndromes aren't necessarily very well understood, but doctors know they exist and the companies in the NIPT space are confident their tests can spot them -- and will do so in their commercial version within the next six to 18 months. ????"I have no doubt that this will become a front-line test across the entire population," Rabinowitz says. "And what's going to drive this to the entire population is deletion syndromes. You really want to be able to screen for these, and to be able to include these in a population-wide screen is an extremely big deal." ????That population-wide adoption will have huge public health impacts, Rabinowitz says, and he's not the only one who thinks so. The NIPT tests themselves only extract the baby's genetic information, so the only thing limiting what they can screen for is doctors' clinical understanding of the genome -- the application of that information in creating therapeutics and making clinical decisions. And with genetic science following its own kind of Moore's Law, those potential applications are growing at a prodigious rate. |