Genotipificación del gen RHD en ADN fetal libre en plasma de embarazadas RhD negativo / Genotyping of the RHD gene in free fetal DNA in plasma of RhD negative pregnant women

Objetivo: Determinar el grupo RhD fetal a través del estudio del gen RHD en ADN fetal que se encuentra libre en plasma de embarazadas RhD negativo. Método: Se analizó la presencia de los genes RHD, SRY y BGLO en ADNfl obtenido de plasma de 51 embarazadas RhD negativo no sensibilizadas, utilizando una qPCR. Los resultados del estudio genético del gen RHD se compararon con el estudio del grupo sanguíneo RhD realizado por método serológico en muestras de sangre de cordón, y los resultados del estudio del gen SRY fueron cotejados con el sexo fetal determinado por ecografía. Se calcularon la sensibilidad, la especificidad, los valores predictivos y la capacidad discriminativa del método estandarizado. Resultados: El gen RHD estaba presente en el 72,5% de las muestras y el gen SRY en el 55,5%, coincidiendo en un 100% con los resultados del grupo RhD detectado en sangre de cordón y con el sexo fetal confirmado por ecografía, respectivamente. Conclusiones: Fue posible deducir el grupo sanguíneo RhD del feto mediante el estudio del ADN fetal que se encuentra libre en el plasma de embarazadas con un método molecular no invasivo desarrollado y validado para este fin. Este test no invasivo puede ser utilizado para tomar la decisión de administrar inmunoglobulina anti-D solo a embarazadas RhD negativo que portan un feto RhD positivo.

Objective: To determine the fetal RhD group through the study of the RHD gene in fetal DNA found free in plasma of RhD negative pregnant women. Method: The presence of the RHD, SRY and BGLO genes in fetal DNA obtained from plasma of 51 non-sensitized RhD negative pregnant women was analyzed using qPCR. The results of the genetic study of the RHD gene were compared with the RhD blood group study performed by serological method in cord blood samples, and the results of the SRY gene study were compared with the fetal sex determined by ultrasound. Sensitivity, specificity, predictive values and discriminative capacity of the standardized method were calculated. Results: The RHD gene was present in 72.5% of the samples and the SRY gene in 55.5%, coinciding 100% with the results of the RhD group detected in cord blood, and with the fetal sex confirmed by ultrasound, respectively. Conclusions: It was possible to deduce the RhD blood group of the fetus through the study of fetal DNA found free in the plasma of pregnant women with a non-invasive molecular method developed and validated for this purpose. This non-invasive test can be used to make the decision to administer anti-D immunoglobulin only to RhD-negative pregnant women carrying an RhD-positive fetus.

Lipoprotein profile modifications during gestation: A current approach to cardiovascular risk surrogate markers and maternal-fetal unit complications / Modificações do perfil lipoproteico durante a gestação: uma abordagem atual demarcadores sugestivos de risco cardiovascular e complicações materno-fetais

Abstract Several changes occur in lipid metabolism during gestation due to hormonal and metabolic changes, which are essential to satisfy the nutritional demands of the maternal-fetal unit development. The gestation shows two distinct periods that begin with fat accumulation, mainly in maternal adipose tissue, and the late phase, characterized by accelerated catabolism, with the increase of fatty acids in the circulation that causes hyperlipidemia, especially the one characterized as hypertriglyceridemia. Maternal hyperlipidemia may be associated with the development of maternal-fetal complications (preterm birth, preeclampsia, vascular complications) and the development of long-term cardiovascular disease. The cardiovascular risk may not only be related to lipoproteins cholesterol content, but also to the number and functionality of circulating lipoprotein particles. This review reports themajor changes that occur in lipoprotein metabolismduring pregnancy and that are associated with the development of dyslipidemias, lipoprotein atherogenic phenotype, and maternal-fetal unit complications.

Resumo Diversas mudanças ocorrem no metabolismo lipídico durante a gestação em função das alterações hormonais e metabólicas, que são essenciais para satisfazer a demanda nutricional ocasionada pelo desenvolvimento da unidade feto-placentária. O período da gestação apresenta dois momentos distintos que iniciam com acúmulo de gordura principalmente no tecido adiposo materno, e a fase tardia, caracterizada por catabolismo acelerado, com aumento de ácidos graxos na circulação causando hiperlipidemia, principalmente a aquela caracterizada como hipertrigliceridemia. A hiperlipidemia materna pode estar associada ao desenvolvimento de complicações materno-fetais (parto prematuro, pré-eclâmpsia, complicações vasculares) e de doenças cardiovasculares, a longo prazo. O risco pode estar relacionado não apenas ao teor de colesterol contido nas frações lipoprotéicas, mas também ao número e a funcionalidade das partículas lipoproteicas. Esta revisão aborda as principais mudanças que ocorrem no metabolismo lipoproteico durante a gravidez, e que estão associadas ao desenvolvimento de dislipidemias, fenótipo aterogênico e complicações maternofetais.

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.

Diagnóstico pré-natal utilizando material fetal isolado do sangue periférico materno / Prenatal diagnosis using fetal material isolated from maternal peripheral blood

As anomalias cromossômicas apresentam grande incidência entre os nativivos e natimortos, constituindo a maior causa de morte fetal em países desenvolvidos, no período perinatal. Tradicionalmente, o diagnóstico dessas cromossomopatias é feito por procedimentos invasivos, que não são isentos de complicações materno-fetais. O desenvolvimento de técnicas que permitem identificação e o isolamento de células fetais e de DNA fetal livre no sangue periférico materno tem permitido o diagnóstico precoce das anomalias cromossômicas, tornando-se, desse modo, uma área de intensas pesquisas. Estudos mais recentes também envolvem a identificação e quantificação de mRNA fetal na circulação materna, o que torna possível a análise da expressão gênica fetal durante a gestação. O resgate de material fetal em sangue periférico materno e sua utilização no diagnóstico de várias doenças fetais é uma área de grande interesse na medicina fetal atual. Estudos são necessários para se avaliar melhor o papel propedêutico dessas novas técnicas, assim como sua aplicabilidade na prática clínica rotineira.

Chromosomal abnormalities show great incidence among live birth and stillbirth, becoming the major fetal death cause during the perinatal period in developed countries. Traditionally, the diagnosis of these chromosomal abnormalities is performed through invasive techniques which are not free from maternal-fetal complications. The development of techniques that allows identification and isolation of fetal cells and free fetal DNA in peripheral maternal blood has afforded the early diagnosis of chromosomal abnormalities and, therefore, become an intensive area of research. Recent studies describe the identification and qualification of fetal mRNA in the maternal circulation, which makes possible fetal gene expression analysis during pregnancy. The identification of fetal material in maternal circulation and its value on the diagnosis of several fetal diseases is a great area of interest in the current fetal medicine. Studies are necessary to evaluate the best propedeutic role of these new techniques, as well as their applicability in the routine clinical practice.

Diagnóstico pré-natal utilizando sangue materno / Prenatal diagnosis using maternal blood

As técnicas de diagnóstico pré-natal têm evoluído de forma acelerada, em especial aquelas que implicam menor invasão fetal. Nesse cenário, grande importância tem sido dispensada às técnicas de detecção de DNA fetal livre (DNA-fl) no sangue materno, as quais apresentam melhor relação custo-benefício quando comparadas às técnicas de enriquecimento e isolamento de células fetais. O DNA-fl pode ser avaliado de forma qualitativa ou quantitativa. Na primeira forma, detectam-se seqüências gênicas fetais de herança exclusivamente paterna com o intuito de selecionar fetos portadores de determinada doença, como a mutação para a fibrose cística ou a identificação de características fetais diferentes das maternas, como a incompatibilidade sanguínea RhD. Assim, os recursos propedêuticos invasivos ficariam reservados apenas para uma pequena parcela dessa população. Na segunda forma, quantifica-se a concentração de DNA-fl para se definir gestantes sob risco para eventos desfavoráveis relacionados a alterações da interface materno-fetal, como abortamento, trabalho de parto pré-termo e pré-eclâmpsia. Cabe às instituições de atenção pré-natal terciária a pesquisa e a aplicação desses recursos, objetivando a redução dos custos e sua maior disponibilização para a sociedade, conseqüentemente oferecendo diagnósticos mais precoces e menores taxas de morbimortalidade materna e fetal.

Prenatal diagnostic techniques are evolving greatly, especially noninvasive procedures. Great importance have been given to the free fetal DNA (ff-DNA) detection in maternal blood presents better cost/benefits relation when compared to enrichment and isolation of fetal cells. The ff-DNA can be analyzed qualitatively or quantitatively forms. In the first form, the fetal paternally derived genetic sequences are detected in order to select which fetuses are affected by determined disease, as the mutation for cystic fibrosis, of to identify fetal characterístics different from his mother's, as in RHD incompatibility. Then, invasive procedures could only be used in part of this population aiming more therapeutics aspects than diagnosis. In the second form, the ff-DNA quantilication can define pregnancies under risk for undesirable outcomes related to anomalies in the maternal-fetal interface, such as abortion, preterm labor and pre-eclampsia. It's expected that tertiary prenatal care centers research can work with those procedures in order to offer early diagnosis and lowest rates of fetomaternal morbimortality.

Actualización en el diagnóstico y manejo de alteraciones hematológicas del feto / Updating in the diagnose and management of hematologic alterations of the fetus

Presentamos una revisión de la literatura de los problemas hematológicos del feto más relevantes, con especial enfoque del diagnóstico y tratamiento prenatal.

Prevention and control of thalassemia at Saraburi Regional Hospital.

OBJECTIVE: To evaluate the program in prevention and control of thalssemia among pregnant women and their spouses, prevention of new cases by screening tests, confirmatory test, genetic counselling, prenatal diagnosis, and selective abortion. SUBJECTS: The pregnant women, attending antenatal care unit, Saraburi center hospital, as well as their spouses. 1 January 2000-31 December 2001 METHOD: As part of the antenatal care assessment, pregnant women before 16 weeks gestation were screened, with pre- and post-test counselling, by osmotic fragility (OF) and dichorophenol indophenol precipitate (DCIP) tests, and confirmed by complete blood count (CBC), mean corpuscular volume (MCV), hemoglobin typing and polymerase chain reaction for alphathal1 (PCR alphathal1) if any of two screening tests was positive. The husbands of those who were carriers of severe thalassemia were encouraged to have thalassemia screening and confirmation. When both the pregnant women and their husbands were carriers of severe thalassemia, the pregnant women would voluntarily perform the prenatal diagnosis. Termination of pregnancy would be offered when the fetus had severe thalassemia. RESULTS: There were 3,739 from 4,214 women (88.7% of all antenatal women), who participated in the program. OF and/or DCIP were positive in 1,742 of 3,739 subjects (46.5%). Of those, 960 from 1,742 (55.1%), had husbands who were willing to have the testing, and OF and/or DCIP were positive in 443 of 960 cases (46.1%). The confirmatory tests revealed carrier and disease of thalassemia, and hemoglobinopathies in 931 of 1,742 women (53.9%), and 135 of 960 husbands (14.0%). The 20 couples who had the possibility of having severe thalassemic newborns, were strongly advised to have prenatal diagnosis. The 12 risk pregnancies had been performed cordocentesis. Finally 3 of 12 (25.0%) fetuses were documented to have severe thalassemia and all of them decided to have selective abortion. CONCLUSIONS: The screening model for thalassemia carriers by using the combination of OF and DCIP is the easy screening model. It can be done quickly, it is inexpensive, therefore it is suitable for large numbers of population screening. The systematic screening, confirmatory of thalassemia diagnosis and prenatal diagnosis are the measure of thalassemia prevention and control, and aims to decrease the number of newborns with severe thalassemia.