J Korean Med Assoc 2014 September; 57(9): 해진단된다운증후군 32예의산전검사에서도감소함을발표이후임신중기산전진단을위한선별검사로서의산전검사가시작되었다. 여기에 human chorionic gonadotropin (hcg), u

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1 CONTINUING EDUCATION COLUMN J Korean Med Assoc 2014 September; 57(9): pissn / eissn 세포유리태아 DNA 를이용한비침습적산전검사의임상적적용 양정인 아주대학교의과대학산부인과학교실 Clinical application of non-invasive prenatal testing using cell free fetal DNA Jeong In Yang, MD Department of Obstetrics and Gynecology, Ajou University School of Medicine, Suwon, Korea Non-invasive prenatal testing using next generation sequencing technology with cell free fetal DNA from the blood of pregnant women has been rapidly adopted as a screening test for the detection of disorders involving chromosomal aneuploidy, especially Down syndrome. However as part of a prenatal recommendation in high-risk group, this laboratory assessment should be accompanied by informed counseling at both pre-test and post-test stages. In low-risk group and multifetal pregnancies, only conventional maternal serum screening tests in the first trimester and/or second trimester in addition to measurement of nuchal translucency should be recommended, until this potential tool has been incorporated into current screening strategic modalities on the basis ofsufficient published data. Key Words: Cell free fetal DNA; Non-invasive prenatal testing; Aneuploidy 서론 최근산모로부터얻은혈액, 즉비침습적방법을통해 다운증후군을발견한놀랄만한일련의연구들이 2011 년 이후보고되었다 [1-6]. 이러한 non-invasive prenatal testing (NIPT) 은산모의혈액속에들어있는세포유리태 아 DNA(cell-free fetal DNA, cff DNA) 를이용하는것으 로산전검사외에도다양한분야의응용가능성에대한기 Received: August 3, 2014 Accepted: August 17, 2014 Corresponding author: Jeong In Yang yangji@ajou.ac.kr Korean Medical Association This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 대감과관심이전세계적으로확산일로에있다. 일반적으로출생전에실시하는산전검사는태아의이상을조기에발견하고이를통해적절한치료를가능케함으로써주산기예후를향상시키기위함이지만주목적은태아염색체이상, 특히가장많은빈도를차지하는이수성 (aneuploidy) 염색체이상중삼배수체 (trisomy) 21, 18, 13 및성염색체수적이상의진단이었다. 따라서분만시모성나이 35 세이상이거나염색체이상임신의과거력, 가족력이있는경우에는산전진단을위한침습적검사가필수적이다. 산모의나이에따라태아염색체이상의위험도는올라가지만실제태아염색체이상의약 70% 는 35세미만의산모에서발생하기때문에침습검사에대한적응증이없는산모에서도산전진단에도움을줄수있는검사가필요하게되었다 년 Merkatz 등 [7] 이신경관결손증의산전검사에사용되던모성혈청알파태아단백치가, 후향적연구를통 세포유리태아 DNA 를이용한비침습적산전검사의임상적적용 771

2 J Korean Med Assoc 2014 September; 57(9): 해진단된다운증후군 32예의산전검사에서도감소함을발표이후임신중기산전진단을위한선별검사로서의산전검사가시작되었다. 여기에 human chorionic gonadotropin (hcg), unconjugated estriol (ue3) 을더한삼중검사 (triple test), inhibin A가추가된사중검사 (quad test) 등이발표되면서임신중기모성혈청산전선별검사로다운증후군의발견율은 80% 까지올라가게되었다 [8]. 임신초기의선별검사는 1994년 Nicolaides 등 [9] 이임신 10-13주에증가된태아목덜미투명대 (fetal nuchal translucency) 를초음파로스캔하여선별검사로, 그리고모성혈청표지자로 pregnancy associated plasma protein A와 β-hcg 를함께측정하여비교적높은발견율의조기선별검사를시행할수있게되었다. 그후임신제일삼분기와제이삼분기에걸쳐시행되는통합선별검사 (integrated screening test) 를통해보다향상된결과를얻게되었다 [10]. 발견율의개선에도불구하고이러한혈청표지자및태아목덜미투명대검사는산전진단의선별검사만을담당하는것이며산전진단을위한태아의유전물질을얻기위해임신제일삼분기에는융모막검사를, 임신 15주이후에는양수검사또는제대천자등 0.5-1% 태아소실의위험성이있는침습적인검사가반드시필요할뿐만아니라선별검사의민감도증가에따른높은위양성률로인해불필요한침습검사의시행횟수역시증가하게된다 [11]. 보다안전하고비침습적인방법이모체혈액내태아유래유전물질을이용하는것으로 1997년 Lo 등 [12] 이모체혈장및혈청에서추출한 cff DNA의 Y-염색체염기서열분석에처음으로성공하였다. 모체혈액내의 cell free DNA 는태반의재형성과정중세포사멸과정을겪은영양막세포 (apoptotic villous trophoblast) 의일부분이물질교환기전을통해모체순환계로들어간것으로실제로는태반기원의유전물질이며이중태아기원의 DNA를 cff DNA라고한다 ( 또는 fetal fraction이라고명칭하여 ff DNA라고도하지만여기서는 cff DNA로통일한다 ). 빠르면배아이식 18 일째부터, 37일경에는대부분의모체혈액내에서발견된다 [13]. Lo 등 [12] 의연구에서는 16.3분의매우짧은반감기를가지는것으로알려졌으나 1시간과 13시간의시기에따라다른반감기를나타내며분만약 2시간후에는대부분, 늦어도출산후 1-2 일이내혈액내에서제거된다 [14,15]. 이처럼매우빠른모체혈액내소멸로인해처음우려와는 달리과거의임신에영향을받지않아다양한분야에적용 가능성이있으며세포내 genomic DNA 와다르게 300 bp 이하의짧은가닥 DNA 로존재한다는장점이있다 [1,16]. 또한 X 염색체연관질환의발견을위한태아성별및 Rh 혈 액형여부를판정하기위한검사는실시간정량중합요소연 쇄반응 (real-time quantitative PCR) 으로거의 100% 에이 르는진단적정확도로임상에사용되고있다 [17-19]. cff DNA 로는필요한많은양을확보하기가어려운점등, 기술 적문제로인해답보상태에있다가임상적용은대규모병렬 염기분석 (massively parallel sequencing, MPS) 이소개된 후다운증후군과같은태아염색체수적이상의 NIPT 가가 능하게되었다 [20,21]. 특히 cff DNA 를이용한고위험임 산부의산전다운증후군검사는 2011 년이후여러회사들로 부터고가의상업적서비스가시작됨으로써현재사용되고 있는선별검사들과적절한통합및임산부유전상담에대한 문제가시작되었다. 따라서본고에서는태아 DNA 를이용 한다운증후군을진단하기위한선별검사또는산전진단검 사로서의 NIPT 현황, 제한점및향후임상적적용에대해 살펴보고자한다. 염기서열분석법기술의발전과 Non-invasive Prenatal Testing 태아이배수체산전진단의성공은염기서열분석법기술의 발전과대용량의바이오데이터를다루는생물정보학의동 반발전이있었기에가능하다. cff DNA 를이용한다운증후 군진단의대표적인염기서열분석기술은 DNA 의미세한양 적차이를민감하게감지할수있는차세대염기서열분석 법 (next-generation sequencing) 이다. 이미국내에 NIPT 에흔히사용되는염기서열분석법에대한자세한리뷰가발 표되었다 [22,23]. 모계기원과태아기원의양측 DNA 분 절을동시에수백만카피로염기서열을분석하고이자료 를각염색체의표준염기서열 (reference genome) 과비교한 772 대한의사협회지

3 Yang JI Clinical application of non-invasive prenatal testing using cell free fetal DNA Maternal blood sample Maternal and fetal cell-free DNA Cell-free DNA sequenced via massively parallel sequencing Alighment and counting Figure 1. The massively parallel genomic sequencing for the non-invasive prenatal detection of fetal chromosomal aneuploidy. 후해당염색체 ( 다운증후군의경우 21 번 ) 의상대적인발현 양의많고적음을 z-score 로계산하여 양성 또는 음성 의 결과를얻게된다. 태아 DNA 분절을모두증폭하는방법을 shotgun MPS 라하고, 21, 18, 13 등진단대상이되는염 색체에해당하는분절만사용하는경우 targeted MPS 라하 며이처럼대량의병렬데이터생산이가능하도록만든자동 화된시퀀서를사용하는방법이차세대염기서열분석법이 다 [24] (Figure 1). 비록고위험군이대상이었지만대규모의 코호트연구를통해다운증후군은위양성률 0.03%, 민감도 100%, 에드워드증후군 (trisomy 18) 위양성률 0.07%, 민감 도 97.4% 의진단적정확도를발표후고가의분석장비와고 도의분석기술인생물정보학을확보한세계적인염색체분 석업체들에의해상업화된서비스가제공되기시작하였다 [4,25] (Table 1). 그외단일염기서열다형성 (single nucleotide polymorphism) 방법을통해인간유전체의약 1.6% 를차지하는단 일염기서열다형성기원의부계또는모계기원의이배수체, 유전자의재조합, 돌연변이등의진단에도사용가능성이있 음을발표하였다 [26]. 영향인자들 NIPT 의성공적인결과를얻기위한가장중요한인자는 모체혈액내에있는 cff DNA 의양으로일반적으로임신 10 주에는약 4%, 임신 주사이에일주일마다약 0.1% 씩증가하며전체모성혈액내세포유리 DNA 의 10-20% 를차지한다 [27]. 4% 미만의적은 cff DNA 양은결과를얻 을수없다. 그외다른생물학적요인들도영향을미칠수 있다. 산모의체중또는체질량지수가가장중요한생물학적 요인이며증가에따라 cff DNA 의양은감소한다. 모성순환 계의희석효과및보다많은양의모체유래혈관세포및지 방세포기원의사멸세포가모성순환계로유입되기때문이 다 [28,29]. 이배수체의타입에따라서도영향을받는데삼배 수체 21 은유입되는 cff DNA 의양이증가하지만삼배수체 13, 18, monosomy X 는감소하는데태반내영양막세포의 강화된세포소멸기전으로풀이된다 [30]. 그외다태임신시 태아의수증가와유입되는 cff DNA 양은비례하지않고오 히려 chorionicity 와무관하게약 50% 로감소하는경향을보 이며쌍태임신의 10-15% 에서는태아염색체이상유무와 무관하게결과를얻을수없을정도로낮은 cff DNA 값을보 이기도한다 [31]. 그외 0.1% 의불일치결과를얻을수있는 데이는정상염색체를보이는태아와태반에국한된모자이 시즘 (confined placental mosaicism) 때문이다. Faas 등 [32] 은세포영양막층및 cff DNA 는 45, X 태반내간엽세포층은 46, XX 인증례를발표하기도하였다. Non-invasive Prenatal Testing 검사시제한점및문제점 국한된검사결과, 개방성신경관결손증의선별검사, 모 성혈청검사시행시부가적으로얻는정보를얻을수없다는 제한점이있다. 태아염색체이상에대한위험도검사는삼 배수체 21, 18, 13, 이배수성염색체와같은매우한정된태 아염색체이수성의선별검사만이가능하므로양수검사시 얻을수있는세포유전학이상소견의약 50% 정도만알수 세포유리태아 DNA 를이용한비침습적산전검사의임상적적용 773

4 J Korean Med Assoc 2014 September; 57(9): Table 1. Comparison of NIPS according to commercial companies Sequenom Verinata Health (Illumina) Ariosa Diagnostics Natera Test name MaterniT21 Plus Verifi Harmony Prenatal Test Platform SEQure Dx technology incorporating s-mps MPS using SAFeR algorithm DANSR incorporating targeted sequencing &FORTE algorithm Harmony Prenatal Test Next generation SNP-based targeted aneuploidy testing Market entry October 2011 March 2012 May 2012 December 2012 Sensitivity (FPR) Trisomy % (0.2%) >99.9% (0.2%) >99% (0.1%) >99% (0%) Trisomy 18 >99.9% (0.3%) 97.3% (0.4%) 98% (0.1%) >99% (<0.1%) Trisomy % (0.9%) 87.5% (0.1%) 96.7% (0.05%) >99% (0%) Monosomy X 94.7% (0.5%) 95.0% (1.0%) 96.7% 91.7% (<0.1%) Sex chromosome trisomies 99.9% 67%-100% 67%-100% >99% Triploidy Undetectable Undetectable Undetectable >99% Modified from Agarwal A, et al. Prenat Diagn 2013;33: [25]. MPS, massive parallel sequencing; DANSR, digital analysis pf selected regions; SNP, single nucleotide polymorphism; FPR, false positive rate. 있으며임산부나이 35세미만의약 75%, 35세이상에서는 43% 의세포유전학이상을발견하지못하게된다 [33,34]. 또한비대칭전위, 결손, 중복등의염색체이상소견은 NIPT 검사로진단할수없으므로초음파검사시태아기형이발견되었을때는침습적인검사와세포유전체마이크로어레이검사가더욱도움이된다 [35,36]. 그외전형적인다운증후군이아닌 21번염색체를포함하는로버트슨형전좌에의해발생하는경우등다운증후군의발생기전을구분하지못하므로다음임신을위한재발위험도의유전상담을할수없다. 근래 NIPT에대한연구결과들이축적되며이러한문제점들도조금씩보완되고있다. 결과의해석면에서검사가가능하도록충분한양의 cff DNA를얻지못한경우앞서말한 uninformative 결과를얻을수있는데이는진단이지연되거나위험도평가시기를놓치는결과로이어질수있으므로가급적임신 10주미만의초기임신시는피하도록한다 [37,38]. 통상적인모성혈청검사를통한선별검사와비교할때 NIPT검사는결과보고까지약 7-10일정도의시간이소요되므로임신 10주에서 20주사이에시행한다. 임신 15-20주에시행하는모성혈청선별검사항목에포함된알파태아단백은개방성신경관결손증선별검사에매우유용하며다음단계로정밀초음파검사를시행하여구조적이상소견을진단할수있을뿐만아니라양수검사를통해아세틸콜린에스테라제검사및양수내알파태아단백치를검사할 수있지만 NIPT는개방성신경관결손증의선별검사에이용할수없다. 따라서결국모성혈청선별검사와 NIPT를병행해야하는문제가발생하게된다 [39]. 또한모체혈청검사는일차적으로태아의이배수성및신경관결손의위험을파악하기위한것이지만그이외에조산, 태아사망, 전자간증, 저체중아등의불량한임신결과와연관이있다. 원인을알수없이알파태아단백치가증가한경우임신과연관된고혈압, 유산, 조산, 자궁내성장지연, 자궁내태아사망, 양수감소증, 태반박리가증가하며, hcg의증가및 ue3 값이감소한경우에도임신예후와관계가있다고보고되었다 [40]. 그러나 NIPT가모성혈청검사를대신할경우임신경과및후기의합병증에대한예측을통해집중적인산전관리의도움을받을수가없다. 임신초기초음파검사는정확한임신주수의판정을통해저체중아및과숙임신의진단율증가, 다태임신의확인및임신예후에영향을주는융모막성의판별, 태반이상및임신제일삼분기에진단가능한태아기형의발견과더불어태아목덜미투명대측정을통해염색체이상, 선천성심장또는흉부기형의고위험군, 불량한주산기예후의고위험군등에대한예측도를향상시킬수없다 [41,42]. 최근보조생식술의발달로인해쌍태임신을포함한다태임신의빈도가올라가고있으며특히이군에속하는임산부들은다태임신, 모성나이의증가라는위험요인외에도다양한산과적위험 774 대한의사협회지

5 Yang JI Clinical application of non-invasive prenatal testing using cell free fetal DNA 인자를가지고있는경우가많아보다 NIPT검사가필요하지만단태임신에비해알려진정보가미미하므로더많은자료의축적, 차별화된생물정보학의계발및임상적검증이우선되어야한다. 또한현재고가의검사비용으로인해공공의료부분으로확대가어렵기때문에적응증이되며검사를받기원함에도불구하고할수없는임상적경우들이발생하게되고다양한윤리적문제들이유발될수있는데실제개인정보차원에서태아의염색체검사결과는정상이었지만임산부의염색체결과는 XXX 로우연히발견되기도한다. 산전 DNA 염기분석 (prenatal DNA sequencing) 은 2013년매사추세츠공과대학교선정 10대주요기술중하나로선정되기도하였으며검사기관, 유전상담의및임상의들은아주기본적인문제이지만환자들과그들의샘플에의무와책임이있다. 특히서비스가가능한검사기관및특허가외국 ( 미국 4개, 중국 1개기관 ) 에집중되어있으므로국내의검사시료가국외로반출되므로원치않는유전정보들이노출될수있는결과를가져오게된다. 시료의먼거리이동은다행히검사결과에영향이거의없는것으로알려져있다. NIPT가선별검사로서의요건을갖추려면저위험군에서의결과가필수적인데지금까지의연구결과는모두고위험군을대상으로이루어진것이다. 다행히저위험군에서의연구가시작되었다는점이다. 저위험군 289명을대상으로한 Fairbrother 등 [43] 의임신제일삼분기연구는 284명중모체혈청검사양성이 4.5% 9.3일이내결과를얻은 NIPT 검사결과는모두음성이었으며이중결과를얻을수없었던경우는 6명 (98.6%) 이었다. 임신중기산모나이 세의저위험군 1,916명에서삼중검사와 NIPT를모두시행한중국에서의연구는 NIPT결과실패율은 3.8%, cut-off 를 270명중일로하였을때삼중검사양성은 249명 (14.3%) NIPT양성은 12명 (0.68%, 11례의태아이배수체, 1례의모성모자이시즘으로인한불일치결과 ) 를얻어 NIPT 검사만보았을때체염색체이배수의민감도 100%, 특이도 99.4%, positive predictive value (PPV) 91.67% 이며삼중검사는민감도 54.5%, 특이도 85.9%, PPV 2.4% 로임신중기저위험군에서도선별검사로서의가능성을시사하였다. 그러나저 위험군의연구는이제걸음마단계로보다많은예에서의연구가시급하다 [44]. 성염색체이배수체연구는앞서 Song 등 [44] 의연구에서총 4예중 2예에서 NIP양성을보여민감도 50%, 특이도 100% 로아직은활발한임상적용은어렵지만단일염기서열다형성의방법이도입되며보다좋은결과에기대를가지고있다. 실제임상에서의활용및상담 2012년도 American College of Obstetricians and Gynecologists (ACOG) 그룹은 cff DNA를이용한 NIPT의적응증으로, 첫째, 분만시산모나이 35세이상, 둘째, 이수성염색체이상을시사하는태아초음파소견, 셋째, 과거삼배수체염색체이상을가진임신력, 넷째, 태아이수성염색체진단을위한선별검사중임신제일삼분기또는제이삼분기선별검사 ( 순차적, 통합또는사중검사결과 ) 가양성으로나온경우, 다섯째, 부모의균형로버트슨형전좌에의한태아삼배수체 13번또는삼배수체 21번의위험도가증가할경우발표하였다 [45]. 또한 NIPT로통상의산전검사, 초음파검사시발견된태아의구조적이상평가및융모막검사또는유전적양수검사의진단적정확도를대신할수는없고, 태아이수성염색체이상의위험도가높은고위험군산모에서는다른산전진단검사가필요한가족내유전질환의유무를파악하기위해검사전유전상담및가족력상담을통해임산부에게충분한정보를제공하도록하였다. 결과의판독은음성일경우태아의염색체수적이상이없다는것을확인하지못하는, 즉위음성률이있으며반대로양성결과를얻었다하더라도위양성률이존재하므로확진을위해침습적산전진단검사가필요함을기본으로하며 NIPTS는하나의대안으로만제시되어야한다고주의하였다. American College of Medical Genetics and Genomics 및 International Society of Prenatal Diagnosis는산전진단에태반기원의세포를이용시에는태아염색체에대한모든정보가나타날수없으므로특히검사전과검사후상담의중요성을강조하였다 [46,47]. 검사전유전상담 세포유리태아 DNA 를이용한비침습적산전검사의임상적적용 775

6 J Korean Med Assoc 2014 September; 57(9): 시 NIPT의목적, 모체혈청을이용한선별검사에비해높은발견율과특히다운증후군에대해높은음성예측률과낮은위양성률로침습적검사기회의감소효과, 결과판정시 ACOG의주의당부와마찬가지로 NIPT검사양성시에는물론침습적인검사를고려해야하지만음성의결과를얻었다할지라도산전진단검사가아니므로선별검사로서의한계점에대한설명이반드시포함되어야함을제안하였다. 검사후상담에는양성또는음성결과시제한점, 태반모자이시즘, 쌍태임신을포함한다태임신시자연발생또는선택적태아감수술을시행받았을때일부태아소실로인한위양성가능성및 uninformative 결과를얻었을때에도침습적확진검사가필요함을설명하도록권고하였는데이것은결과의판정이개개인의위험도를각각계산해서맞춤상담을시행하여야한다는점을강조한것이다. 세전문가집단에의한임상진료지침은분명 NIPT검사를, 다양한모체혈청선별검사에비해분명높은민감도와특이도의산전선별검사를제공가능하며최종결과를임신중기가아닌제일삼분기에알수있어실제사용자인임산부특히고위험군산모가불안감을느끼는시간을줄여줄수있을뿐만아니라점점증가하고있는고령임산부에게태아유산의위험성이있는침습적검사를실시하게될임상적경우의수들을줄여줌으로써고위험자체가가지고있는고유의유산기회를낮춰보다임신예후를좋게할수있는큰장점을가진희망적인검사로받아들이고있으나제한점으로인해그임상적용의확대에는매우조심스러우며특히일선에서직접적인의료서비스를제공시주의가필요하다. 경우 NIPT검사를시행하며양성인경우통상의융모막검사또는양수검사를, 음성인경우더이상의선별검사를시행하지않는다. 임신제일삼분기의태아목덜미투명대의측정은지속하도록한다. 분만시산모나이 35세이상, 이수성염색체이상을시사하는태아초음파소견, 과거삼배수체염색체이상을가진임신력등의고위험군에서는임신 10주이후 NIPT검사시행을권유한다. 모성알파단백측정여부는국내에서모성혈청검사가개방성신경관결손증의진단에어느정도의기여도가있는지다기관연구를통한자료축적이후의결정이바람직할것으로보인다. 급격히변하는 NIPT 연구의흐름에비추어보았을때임상적의사결정흐름은추후많은변화를겪을것으로예측된다. 향후임상적적용의기대 전자간증의산화스트레스로인한태반내영양막세포들의세포사멸기전이촉진되므로모체순환계로 cff DNA의유입이증가되며된다 [48]. 또한조기진통및자궁내태아발육부전의경우에도 cff DNA의양이많아지는것을발견하였다 [49,50]. 따라서모체혈액내 cff DNA 양의변화는본질환들의병태생리의이해, 조기진단을위한바이오마커계발, 태반의기능및건강상태를예측하는데적용할수있을것이다. 결론 국내에서의적용 NIPT는전체염색체지도를얻을수있는결과가아니므로현재까지는산전선별검사로분류되어야하며저위험군의양성예측률은높지않으므로 universial screening 이아닌조건적적응증을가진고위험군에서이차적선별검사로제안한다. 즉임신제일삼분기의모체혈액을이용한태아염색체선별검사를시행하고그후위험도에따라고위험군의 NIPT는진단적정확도및유용성이매우높은강력하고새로운, 매력적인산전검사방법이지만실제임상적용을둘러싸고뜨거운논쟁과관심을받고있다. 특히이른검사시기, 높은발견율, 낮은위양성률로인해침습적검사를줄일수있다는장점뿐만아니라태아와모체모두에게안전한검사이다. 현재까지는전체임산부를대상으로실시하는태아이수성염색체의선별검사로자리매김할수는없으나저위험군에서의보다많은대규모연구가선행되고충분한유전 776 대한의사협회지

7 Yang JI Clinical application of non-invasive prenatal testing using cell free fetal DNA 상담과비용문제를포함한사회적지지, 윤리적, 법적문제 및연구수행기관들의정도관리를아우를수있는적절한가 이드라인을만든다면고위험임산부를위한산전선별검사 로서의가능성이충분하다. 특히최근이삼년동안에여러 대중적 NIPT 서비스기관및모성센터들의집중적, 몰입적이 고도경쟁적인연구를통해이루어진괄목할만한검사방법 의개선등눈부신가시적연구성과들을보았을때염색체 수적이상선별검사는아직은그시기를알수없지만결국 태아의전체유전체지도또는엑솜염기서열분석으로이어 질수있으므로빠른시일내임상진료지침의마련이필수적 이다. 또한태아이수성염색체검사외에도전자간증, 자궁 내태아발육부전등태반기원임신특이성질환들의병태생 리이해와조기진단을위한생물학적바이오마커계발등과 같은다양한임상적적용이가능하며이를통해많은임상의 와연구자들의노력을통해불량한주산기예후향상및모성 건강의발전에이바지할수있을것이다. 찾아보기말 : 세포유리태아 DNA; 비침습적산전검사 ; 이배수체 ORCID Jeong In Yang, REFERENCES 1. Chiu RW, Akolekar R, Zheng YW, Leung TY, Sun H, Chan KC, Lun FM, Go AT, Lau ET, To WW, Leung WC, Tang RY, Au-Yeung SK, Lam H, Kung YY, Zhang X, van Vugt JM, Minekawa R, Tang MH, Wang J, Oudejans CB, Lau TK, Nicolaides KH, Lo YM. Non-invasive prenatal assessment of trisomy 21 by multiplexed maternal plasma DNA sequencing: large scale validity study. BMJ 2011;342:c Palomaki GE, Kloza EM, Lambert-Messerlian GM, Haddow JE, Neveux LM, Ehrich M, van den Boom D, Bombard AT, Deciu C, Grody WW, Nelson SF, Canick JA. DNA sequencing of maternal plasma to detect Down syndrome: an international clinical validation study. Genet Med 2011;13: Ashoor G, Syngelaki A, Wagner M, Birdir C, Nicolaides KH. Chromosome-selective sequencing of maternal plasma cell-free DNA for first-trimester detection of trisomy 21 and trisomy 18. Am J Obstet Gynecol 2012;206:322.e1-322.e5. 4. Norton ME, Brar H, Weiss J, Karimi A, Laurent LC, Caughey AB, Rodriguez MH, Williams J 3rd, Mitchell ME, Adair CD, Lee H, Jacobsson B, Tomlinson MW, Oepkes D, Hollemon D, Sparks AB, Oliphant A, Song K. Non-Invasive Chromosomal Evaluation (NICE) Study: results of a multicenter prospective cohort study for detection of fetal trisomy 21 and trisomy 18. Am J Obstet Gynecol 2012;207:137.e1-137.e8. 5. Sparks AB, Struble CA, Wang ET, Song K, Oliphant A. Noninvasive prenatal detection and selective analysis of cell-free DNA obtained from maternal blood: evaluation for trisomy 21 and trisomy 18. Am J Obstet Gynecol 2012;206:319.e1-319.e9. 6. Zimmermann B, Hill M, Gemelos G, Demko Z, Banjevic M, Baner J, Ryan A, Sigurjonsson S, Chopra N, Dodd M, Levy B, Rabinowitz M. Noninvasive prenatal aneuploidy testing of chromosomes 13, 18, 21, X, and Y, using targeted sequencing of polymorphic loci. Prenat Diagn 2012;32: Merkatz IR, Nitowsky HM, Macri JN, Johnson WE. An association between low maternal serum alpha-fetoprotein and fetal chromosomal abnormalities. Am J Obstet Gynecol 1984;148: ACOG Practice Bulletin No. 77: screening for fetal chromosomal abnormalities. Obstet Gynecol 2007;109: Nicolaides KH, Brizot ML, Snijders RJ. Fetal nuchal translucency: ultrasound screening for fetal trisomy in the first trimester of pregnancy. Br J Obstet Gynaecol 1994;101: Malone FD, Canick JA, Ball RH, Nyberg DA, Comstock CH, Bukowski R, Berkowitz RL, Gross SJ, Dugoff L, Craigo SD, Timor-Tritsch IE, Carr SR, Wolfe HM, Dukes K, Bianchi DW, Rudnicka AR, Hackshaw AK, Lambert-Messerlian G, Wald NJ, DʼAlton ME; First- and Second-Trimester Evaluation of Risk (FASTER) Research Consortium. First-trimester or second-trimester screening, or both, for Downʼs syndrome. N Engl J Med 2005;353: Mujezinovic F, Alfirevic Z. Procedure-related complications of amniocentesis and chorionic villous sampling: a systematic review. Obstet Gynecol 2007;110: Lo YM, Corbetta N, Chamberlain PF, Rai V, Sargent IL, Redman CW, Wainscoat JS. Presence of fetal DNA in maternal plasma and serum. Lancet 1997;350: Guibert J, Benachi A, Grebille AG, Ernault P, Zorn JR, Costa JM. Kinetics of SRY gene appearance in maternal serum: detection by real time PCR in early pregnancy after assisted reproductive technique. Hum Reprod 2003;18: Lo YM, Zhang J, Leung TN, Lau TK, Chang AM, Hjelm NM. Rapid clearance of fetal DNA from maternal plasma. Am J Hum Genet 1999;64: Yu SC, Lee SW, Jiang P, Leung TY, Chan KC, Chiu RW, Lo YM. High-resolution profiling of fetal DNA clearance from maternal plasma by massively parallel sequencing. Clin Chem 2013; 59: Chan KC, Zhang J, Hui AB, Wong N, Lau TK, Leung TN, Lo KW, Huang DW, Lo YM. Size distributions of maternal and fetal DNA in maternal plasma. Clin Chem 2004;50: Hyett JA, Gardener G, Stojilkovic-Mikic T, Finning KM, Martin PG, Rodeck CH, Chitty LS. Reduction in diagnostic and therapeutic interventions by non-invasive determination of fetal sex in early pregnancy. Prenat Diagn 2005;25: 세포유리태아 DNA 를이용한비침습적산전검사의임상적적용 777

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9 Yang JI Clinical application of non-invasive prenatal testing using cell free fetal DNA 44. Song Y, Liu C, Qi H, Zhang Y, Bian X, Liu J. Noninvasive prenatal testing of fetal aneuploidies by massively parallel sequencing in a prospective Chinese population. Prenat Diagn 2013;33: ACOG Committee Opinion No. 545: noninvasive prenatal testing for fetal aneuploidy. Obstet Gynecol 2012;120: Gregg AR, Gross SJ, Best RG, Monaghan KG, Bajaj K, Skotko BG, Thompson BH, Watson MS. ACMG statement on noninvasive prenatal screening for fetal aneuploidy. Genet Med 2013; 15: Hahn S, Rusterholz C, Hosli I, Lapaire O. Cell-free nucleic acids as potential markers for preeclampsia. Placenta 2011;32 Suppl:S17-S Benn P, Borell A, Chiu R, Cuckle H, Dugoff L, Faas B, Gross S, Johnson J, Maymon R, Norton M, Odibo A, Schielen P, Spencer K, Huang T, Wright D, Yaron Y. Position statement from the aneuploidy screening committee on behalf of the board of the international society for prenatal diagnosis. Prenat Diagn. 2013;33: Farina A, LeShane ES, Romero R, Gomez R, Chaiworapongsa T, Rizzo N, Bianchi DW. High levels of fetal cell-free DNA in maternal serum: a risk factor for spontaneous preterm delivery. Am J Obstet Gynecol 2005;193: Al Nakib M, Desbriere R, Bonello N, Bretelle F, Boubli L, Gabert J, Levy-Mozziconacci A. Total and fetal cell-free DNA analysis in maternal blood as markers of placental insufficiency in intrauterine growth restriction. Fetal Diagn Ther 2009;26: Peer Reviewers Commentary 본논문은세포유리태아 DNA 를이용한비침습적산전검사중 NGS 를활용한염색체수적이상태아의선별검사를중심으로현 재임상에적용할때고려하여할제한점, 영향인자, 임상활용등 다양한내용이기존에보고된자료들을근거로제시한종설이다. 현재 NGS 를활용한비침습적산전검사가국내에빠르게보급되 고있는상황에서본논문은실제임상에서이러한검사를요구하 는환자들에게검사에대한적절한상담을하기위한기반자료로 활용될가치가있으며, 이검사법의국내도입에있어적절한기준 을확립하기위한기본적인방향을제시하고있다는점에서의의 가있는논문이라생각된다. [ 정리 : 편집위원회 ] 세포유리태아 DNA 를이용한비침습적산전검사의임상적적용 779