Practice of clinical application of noninvasive prenatal testing based on cell-free fetal DNA / 中华医学遗传学杂志

OBJECTIVE@#To assess the application value of noninvasive prenatal testing (NIPT) based on cell-free fetal DNA.@*METHODS@#The results of 2777 cases of basic and extended NIPT were retrospectively analyzed. The clinical data and outcome of pregnancy were analyzed, in addition with the diagnosis rate and testing efficiency.@*RESULTS@#Among the 2777 pregnant women, 1192 (42.9%) had accepted basic NIPT and 1585 (57.1%) accepted extended NIPT. With a failure rate of 0.1%, 8 and 6 cases were reported respectively as high-risk pregnancies for trisomy 21 and sex chromosomal abnormalities. Other genetic abnormalities were detected in 32 cases. The positive predictive value for trisomy 21 was 85.7%, and one case of 47,XXX was diagnosed among 3 women with high risks for sex chromosomal abnormalities. For those with a high risk for other genetic abnormalities, pregnant diagnosis rates of basic and extended NIPT were 71.4% (5/7) and 68.2% (15/22), respectively. Seven copy number variations (CNVs) were confirmed, including one pathogenic CNV, one likely pathogenic CNV and 5 variants of unknown significance. Among 6 cases with high-risk of maternal CNVs, 5 fetuses and the mothers were confirmed to be carriers. No CNV was detected in the remainder fetus by chromosomal microarray analysis, while its mother was a carrier of the corresponding CNV.@*CONCLUSION@#NIPT has shown a relatively high positive predictive value for the screening of trisomy 21 and maternal CNVs but with a limited efficiency for the discovery of fetal CNVs. For other genetic abnormalities signaled by NIPT, informed choice by the pregnant women during pre-testing consultation is recommended. Invasive prenatal diagnosis should be considered in the combination of NIPT reports and fetal ultrasound, while the residual risks should be fully informed.

Retrospective and cost-effective analysis of the result of Changsha Municipal Public Welfare Program by Noninvasive Prenatal Testing / 中华医学遗传学杂志

OBJECTIVE@#To assess the practical and health economical values of non-invasive prenatal test (NIPT) in Changsha Municipal Public Welfare Program.@*METHODS@#A retrospective analysis was carried out on 149 165 women undergoing NIPT test from April 9, 2018 to December 31, 2019. For pregnant women with high risks, invasive prenatal diagnosis and follow-up of pregnancy outcome were conducted. The cost-benefit of NIPT for Down syndrome was analyzed.@*RESULTS@#NIPT was carried out for 149 165 pregnant women and succeeded in 148 749 cases (99.72%), for which outcome were available in 148 538 (99.86%). 90% of pregnant women from the region accepted the screening with NIPT. 415 (0.27%) were diagnosed as high risk. Among these, 381 (91.81%) accepted amniocentesis, which led to the diagnosis of 212 cases of trisomy 21 (PPV=85.14%), 41 cases with trisomy 18 (PPV=48.81%) and 10 cases with trisomy 13 (PPV=20.83%). The sensitivity and specificity of NIPT for trisomy 21, trisomy 18 and trisomy 13 were (97.70%, 99.98%), (97.62%, 9.97%) and (100%, 99.97%), respectively. In addition, 213 and 30 cases were diagnosed with sex chromosomal aneuploidies (PPV=46.2%) and other autosomal anomalies (PPV=16.57%), respectively. For Down syndrome screening, the cost and benefit of the project was 120.79 million yuan and 1,056.95 million yuan, respectively. The cost-benefit ratio was 1: 8.75, and safety index was 0.0035.@*CONCLUSION@#NIPT is a highly accurate screening test for trisomy 21, which was followed by trisomy 18 and sex chromosomal aneuploidies, while it was less accurate for other autosomal aneuploidies. The application of NIPT screening has a high health economical value.

Preparation and evaluation of quality management samples for noninvasive prenatal screening / 中华医学遗传学杂志

OBJECTIVE@#To prepare a quality control sample for non-invasive prenatal screening (NIPS) and evaluate its quality and stability.@*METHODS@#According to the biological characteristics of cell-free fetal DNA derived from the plasma of pregnant women, the simulated samples were prepared by mixing genomic DNA fragments derived from individuals with trisomy 21, trisomy 18 and trisomy 13 and background plasma. The samples were then compared with commercially made quality control products tested on various NIPS platforms and stored at -80℃, -20℃, 4℃, 24℃ and 37℃ for various periods of time.@*RESULTS@#The simulated samples have attained the expected results and could be detected on various platforms and stored at -80℃and -20℃ for at least 30 days.@*CONCLUSION@#A simulated sample was successfully prepared and possessed good stability. It can be used as the quality control sample for NIPS.

Utilidad de la evaluación USG Doppler de las arterias uterinas entre las semanas 11 y 13+6 y su aplicación en las calculadoras de riesgo para predecir preeclampsia / Usefulness of the USG Doppler evaluation of the uterine arteries between weeks 11 and 13+6 and its application in risk calculators to predict preeclampsia / Utilidade da avaliação USG Doppler das artérias uterinas entre as semanas 11 e 13+6 e sua aplicação em calculadoras de risco para prever pré-eclâmpsia

Introducción. La preeclampsia es la primera causa de muerte materna directa en Colombia y la segunda a nivel mundial. El desarrollo de estrategias de predicción y prevención puede disminuir las complicaciones y secuelas ocasionadas por dicha enfermedad. El Doppler de arterias uterinas entre las semanas 11 y 13+6 como prueba independiente o en combinación con factores maternos o pruebas bioquímicas permite tasas de detección de preeclampsia temprana ≥ 90% a partir de la implementación de distintos cribados. La validez de dicha prueba diagnóstica presenta una sensibilidad del 47.8% y especificidad del 92.1% para la detección de preeclampsia temprana; con una sensibilidad del 26.4% y especificidad del 93.4% para predecir preeclampsia en cualquier etapa. División de los temas tratados. En esta revisión de tema se aborda la utilidad de esta medición, se habla de la realización de la técnica en cuestión y, por último, se revisan las herramientas estandarizadas que están disponibles en la actualidad junto con su accesibilidad y precisión. Conclusiones. La evidencia empírica que respalda la validez de las herramientas disponibles hoy en día para el tamizaje de preeclampsia a través de la evaluación por ultrasonografía Doppler de las arterias uterinas es significativa. Al ser Colombia un país que presenta una prevalencia alta de preeclampsia, conocer la utilidad de esta medición favorece una vigilancia temprana y oportuna, lo que disminuye los posibles desenlaces desfavorables para las maternas.

Introduction. Preeclampsia is the primary cause of direct maternal death in Colombia and the second globally. The development of prediction and prevention strategies can reduce complications and consequences caused by this disease. The uterine arteries Doppler between weeks 11 and 13+6 as an independent test or in combination with maternal factors or biochemical tests allows for early detection rates for preeclampsia of ≥90% from the implementation of different sieving. The validity of this diagnostic test has a sensitivity of 47.8% and specificity of 92.1% for the early detection of preeclampsia; with a sensitivity of 26.4% and specificity of 93.4% to predict preeclampsia at any stage. Division of Covered Topics. This topic review covers the usefulness of this measurement. It discusses the performance of the technique in question and, lastly, the standardized tools currently available are reviewed together with the accessibility and accuracy. Conclusions. The empirical evidence that supports the validity of the tools available today for the screening of preeclampsia via Doppler ultrasound evaluation of the uterine arteries is significant. As Colombia is a country with a high prevalence of preeclampsia, knowing the usefulness of this measurement favors early and timely surveillance, which reduces possible unfavorable outcomes for mothers.

Introdução. A pré-eclâmpsia é a principal causa de morte materna direta na Colômbia e a segunda no mundo. O desenvolvimento de estratégias de predição e prevenção pode reduzir as complicações e sequelas causadas pela doença. O Doppler da artéria uterina entre as semanas 11 e 13+6 como um teste independente ou em combinação com fatores maternos ou testes bioquímicos permite taxas de detecção de pré-eclâmpsia precoce≥90% a partir da implementação de diferentes exames. A validade desse teste diagnóstico tem sensibilidade de 47,8% e especificidade de 92,1% para a detecção de pré-eclâmpsia precoce; com uma sensibilidade de 26,4% e especificidade de 93,4% para prever pré-eclâmpsia em qualquer fase. Divisão dos tópicos abordados. Esta revisão de tópicos aborda a utilidade desta medição, discute a realização da técnica em questão e, por fim, são revisadas as ferramentas padronizadas que estão disponíveis atualmente, juntamente com sua acessibilidade e precisão. Conclusões. A evidência empírica que apoia a validade das ferramentas disponíveis atualmente para rastreamento de pré-eclâmpsia por meio da avaliação de ultrassom Doppler das artérias uterinas é significativa. Como a Colômbia é um país com alta prevalência de pré-eclâmpsia, conhecer a utilidade dessa medição favorece a vigilância precoce e oportuna, o que reduz possíveis resultados desfavoráveis para mulheres maternas.

Analysis to the failure rate and causes of noninvasive prenatal testing based on high-throughput sequencing / 中华医学遗传学杂志

OBJECTIVE@#To analyze the cause and pregnancy outcome for non-reportable cell-free DNA (cfDNA) results during non-invasive prenatal testing (NIPT).@*METHODS@#cfDNA was extracted from maternal plasma from 5898 singleton pregnancies at 12 to 22 gestational weeks and underwent NIPT with strict quality control standards. For those with sub-standard results, redraw or invasive prenatal procedures were recommended.@*RESULTS@#Among the 5898 cases, 32 have failed for the initial NIPT, including 17 cases with substandard cffDNA%, 10 cases with data fluctuation after twice library constructing and sequencing, and 5 cases with unidentifiable sex chromosome abnormalities. For these 32 cases, 2 directly underwent amniocentesis, and karyotyping analysis showed both were normal. Six of the 30 redrawn cases finally turned out to be nonreportable. The final nonreportable rate was therefore 0.1% (8/5898). Of the redrawn cases, 1 trisomy 21, 1 trisomy 18 and 1 trisomy 13 high risk-cases were identified, which were all confirmed to be false positive. Among the 6 nonreportable cases, 2 women underwent invasive prenatal testing, and 1 was found to have a normal fetal karyotype, while another was found to have an abnormal karyotype of mos45,X[32]/46,XY[18]. The other 4 nonreportable cases who did not accept invasive prenatal testing have all reported normal child development at follow-up.@*CONCLUSION@#The main reason for nonreportable NIPT results was low cffDNA%. The high success rate of the redrawn cases has effectively increased the overall NIPT success rate and reduced the number of the cases necessitating invasive prenatal diagnosis. The initially nonreportable women may consider retesting after careful counseling with informed consent.

Noninvasive prenatal screening for twin pregnancy: an analysis of 2057 cases / 浙江大学学报·医学版

OBJECTIVE@#To analyze the results of noninvasive prenatal screening (NIPS) for fetal chromosome aneuploidy in twin pregnancy.@*METHODS@#A total of 2057 women with twin-pregnancy between 12-26 weeks were recruited from Women's Hospital, Zhejiang University School of Medicine, Hangzhou Municipal Women's Hospital and Jiaxing Maternal and Child Health Hospital during February 2015 to August 2018. The cell-free DNA was extracted from the peripheral blood sample for DNA library, and non-invasive prenatal testing (NIPT) was performed by high-throughput sequencing technique. The fetal karyotype analysis or neonatal karyotype analysis was performed in pregnant women with fetal chromosome aneuploidy, and all subjects were followed up. The efficiency of NIPS testing for twin aneuploidy was calculated.@*RESULTS@#NIPS revealed chromosome abnormalities in 11 out of 2057 twin pregnant women, 9 cases were confirmed chromosome abnormalities, 2 cases were normal and no false negative cases. In this screening, the detection rate, sensitivity, specificity, positive predictive value, false positive rate of NIPS were 100.00%, 100.00%, 99.90%, 81.82%, 0.10%. Those were 100.00%, 100.00%, 99.95%, 87.50% and 0.05% for trisomy 21, 100.00%, 100.00%, 100.00%, 100.00%, 0.00% for trisomy18, and the specificity and false positive rate for trisomy13 were 99.95% and 0.05%, respectively.@*CONCLUSIONS@#NIPS can detect fetal chromosomal aneuploidy rapidly and accurately in twin pregnancies,and it is of value in clinical application.

Development of an Extraction Protocol for Fetal Sexing from the Fourth Week of Gestation by Real Time PCR

Abstract Low number of fetal cells in maternal blood limited the use of fetal materials in diagnostic and clinical applications. This research developed a technology which allowed the extraction of fetal DNA by a non-invasive method that offers no risk to the mother or fetus. A total of 132 pregnant women participated in this inquiry. The DNA extraction was performed employing an in-house method based on guanidine thiocyanate and magnetic bead. For the amplification it was used the Quantifier Y Kit™. The fetal sexing analysis of the 132 pregnant women were 100% in agreement with the ultrasound. Sensitivity and specificity for detection of Y chromosome sequences was possible using Real-Time Polymerase Chain Reaction since the 4th week of gestation. This non-invasive early determination could be employed in fetal gender and also to be extended to detection of genetic diseases in the shortest possible time avoiding invasive methods that puts the fetus at risk.

Resultado de estudio prenatal invasivo para el diagnóstico de aneuploidía en el Hospital Sótero del Río / Results of an invasive prenatal study for the diagnosis of aneuploidy at Hospital Sótero del Río

ANTECEDENTES: Las aneuploidías y malformaciones congénitas son causa importante de morbi-mortalidad perinatal e infantil en Chile. OBJETIVO: Evaluar la realidad local del diagnóstico genético antenatal para mejorar el resultado perinatal. MÉTODOS: Estudio retrospectivo y descriptivo. Se realizó amniocentesis a embarazadas con indicación de estudio genético prenatal por sospecha ecográfica de alteraciones cromo-sómicas, entre octubre de 2010 y marzo de 2015, en el Hospital Sótero del Río. RESULTADOS: Los hallazgos ecográficos más frecuentes fueron: cardiopatías congénitas, malformaciones del sistema nervioso central y restricción de crecimiento fetal precoz. 164 pacientes aceptaron el estudio invasivo antenatal, obteniéndose resultados de 154. El promedio de edad materna y edad gestacional del examen fueron 30 años y 27+3 semanas, respectivamente. En embarazos con trisomía 21 y 13, el 71% de las pacientes tenía sobre 35 años. Un 31% de las muestras presentaron cariotipo anormal, siendo la más frecuente la trisomía 21 (14%), trisomía 18 (9%), monosomía X (4,5%) y trisomía 13 (2,6%). CONCLUSIÓN: El diagnóstico genético prenatal permite un adecuado manejo perinatal, coordinación apropiada entre las unidades de Obstetricia y Neonatología, y la preparación de las pacientes y sus familias para un pronóstico perinatal adverso.

BACKGROUND: Malformations and aneuploidy are a major cause of perinatal morbidity and mortality in Chile. Invasive techniques are offered to determine the fetal karyotype, when there is an abnormal finding in the ultrasound. AIMS: To assess the local situation of prenatal genetic diagnosis to improve the management of this population. METHODS: This is a retrospective and descriptive study of patients from october 2010 to march 2015, who had an amniocentesis for genetic testing due suspected fetal malformations or aneu-ploidy. RESULTS: The sonographic findings most frequently found were: congenital heart disease, malformations of the central nervous system and early growth restrictions. 164 patients agree to perform invasive prenatal genetic, obtaining 154 results. The average maternal age was 30 years and the mean gestational age at amniocentesis was 27+3 weeks. In trisomy 21 pregnancies, 71% of patients were higher than 35 years. 31% of the samples had abnormal karyotype: trisomy 21 (14%), trisomy 18 (9%), Turner's syndrome (4.5%) and trisomy 13 (3%). CONCLUSIONS: Prenatal genetic diagnosis allows appropriate perinatal management and contributes to prepare the patient and their families for an adverse perinatal outcome.

Incorporación del estudio de ADN fetal en sangre materna al cribado de cromosomopatías / Incorporation of the study of fetal DNA in maternal blood to the screening of chromosomal diseases

OBJETIVO: Evaluar la efectividad del cribado combinado de primer trimestre para la detección prenatal de aneuploidías tras 6 años de implantación en nuestro servicio y su repercusión en la disminución de pruebas diagnósticas invasivas. Se propone establecer un protocolo para incorporar el estudio de ADN fetal en sangre materna a partir de las revisiones bibliográficas publicadas. MÉTODO: Se evaluó el riesgo de anomalía cromosómica fetal en 3177 gestaciones mediante cribado combinado de primer trimestre entre enero de 2011 y diciembre de 2014. Se revisaron las amniocentesis realizadas desde que se instauró el cribado combinado en 2008 comparándolas con las de los 5 años anteriores. RESULTADOS: La tasa de detección del cribado para trisomía 21 fue del 94,4% y la tasa de falsos positivos de 6,4%. En el año 2005 estábamos realizando 194 amniocentesis, tras 6 años de implantación del cribado, en el año 2013 se realizaron 35 amniocentesis lo que implica una disminución del 70%. CONCLUSIONES: El cribado combinado de primer trimestre ha demostrado una mayor tasa de detección para trisomía 21 que el cribado de segundo trimestre y/o la edad materna, además de que ha llevado a una importante reducción en el número de pruebas invasivas. En los próximos años la incorporación del estudio de ADN fetal mejorará la detección de aneuploidías, con una drástica disminución de las pruebas invasivas por lo que se hace necesario la implantación de nuevos protocolos.

AIMS: To evaluate the effectiveness of first trimester combined screening in the prenatal detection of aneuploidy after 6 years of implantation in our service and its impact in reducing invasive diagnostic tests. It is proposed to establish a protocol to incorporate the study of fetal DNA in maternal blood from published literature reviews. METHODS: The risk of fetal chromosomal anomalies was assessed in 3177 pregnancies with first trimester combined screening between January 2009 and December 2014. The amniocenteses performed were checked against those of the previous 5 years. RESULTS: The detection rate of screening for trisomy 21 was 94.4% and the false-positive rate was 6.4%. In 2005 there were 194 amniocenteses. In 2013, 5 years after the introduction of screening, 68 amniocenteses were performed, representing a 70% reduction in invasive procedures. CONCLUSIONS: First trimester combined screening has shown a higher detection rate for trisomy 21 that the second trimester screening and/or maternal age, and has substantially reduced the use of invasive prenatal diagnostics procedures. In the coming years, the incorporation of the study of fetal DNA improve the detection of aneuploidys with a drastic reduction of invasive tests so that, the implementation of new protocols is necessary.

Obtención transcervical de células fetales para el diagnóstico prenatal temprano mínimamente invasivo / Transcervical harvesting of fetal cells for early prenatal diagnosis minimally invasive

In the last decade, many studies have documented the presence of fetal cells in samples collected transcervically in early pregnancy. Since fetal cells are present in these samples as early as 7 weeks' gestation, and some of the methods for sample collection (i.e. mucus collection) appear absolutely non-invasive, this approach is regarded as an earlier and safer alternative to all the techniques currently used for prenatal genetic diagnosis. Our studies in this field have contributed to assess the efficacy of different methods for the collection and analysis of transcervical cell samples; all in all it seems that intrauterine lavage the only valuable option, since fetal cells are present in most samples and at a very high rate. In addition, our experience shows that fetal cells in these samples can be reliably identified, sorted under microscope, and then analysed by many different procedures among which QF-PCR is probably the most promising; indeed, this latter technique enables the rapid and simultaneous assessment of the chromosomes most commonly involved in aneuploidies. Further work is required to assess the impact of transcervical cell sampling, and notably of intrauterine lavage, in continuing pregnancies before the possible clinical use of these techniques.